A loop-heat-pipe heat sink with parallel condensers for high-power integrated LED chips

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换热器英语文献

College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100022, PR China Received 23 October 2004; received in revised form 23 May 2005; accepted 10 June 2005 Available online 27 July 2005
Abቤተ መጻሕፍቲ ባይዱtract
In this part of the paper, the performance of the simultaneous charging/discharging operation modes of the heat pipe heat exchanger with latent heat storage is experimentally studied. The experimental results show that the device may operate under either the ﬂuid to ﬂuid heat transfer with charging heat to the phase change material (PCM) or the ﬂuid to ﬂuid heat transfer with discharging heat from the PCM modes according to the initial temperature of the PCM. The melting/solidiﬁcation curves, the performances of the heat pipes and the device, the inﬂuences of the inlet temperature and the mass ﬂow rate of the cold water on the operation performance are investigated by extensive experiments. The experimental results also disclose that under the simultaneous charging/discharging operation mode, although the heat transfer from the hot water directly to the cold water may vary, it always takes up a major part of the total heat recovered by the cold water due to the very small thermal resistance compared with the thermal resistance of the PCM side. The melting/solidiﬁcation processes taking place in the simultaneous charging/discharging operation are compared with those in the charging only and discharging only processes. By applying a simpliﬁed thermal resistance analysis, a criterion for predicting the exact operation modes was derived and used to explain the observed experimental phenomena. Ó 2005 Elsevier Ltd. All rights reserved.

VBA-OM-L007-D 三路阀门残压解压阀腾力调节阀方向控阀操纵器ＡＭＡＦ三路阀门残压解压

Operating location
! CAUTION
ɾDo not install the product where it can be exposed to rain or direct sunlight. ɾDo not install the product where it can be affected by vibration.
Model
Bolt size Tightening torque
! CAUTION ᶃCarrying
VBA1˘A
M5
VBA2˘A, 4˘A
M10
3Nm 24Nm
ɾHold both ends when carrying by hand. Do not hold the handle.
If the handle comes off, the body will fall and it may cause injury.
! CAUTION ᶃFlushingɾɾɾCare should be taken especially for the precision parts.
ɾBefore piping, flush pipes to remove cutting chips, cutting oil, and dust which may cause malfunction or lower the durability of the booster regulator.
Port size
1/8
1/4
3/8
1/2
Tightening torque 7to9Nm 12 to 14Nm 22 to 24Nm 28 to 30Nm

ɾWhen mounting the silencer and the elbow for silencer, hold the end of the body (the

Glider Flying Handbook说明书

Glider Flying Handbook2013U.S. Department of TransportationFEDERAL AVIATION ADMINISTRATIONFlight Standards Servicei iPrefaceThe Glider Flying Handbook is designed as a technical manual for applicants who are preparing for glider category rating and for currently certificated glider pilots who wish to improve their knowledge. Certificated flight instructors will find this handbook a valuable training aid, since detailed coverage of aeronautical decision-making, components and systems, aerodynamics, flight instruments, performance limitations, ground operations, flight maneuvers, traffic patterns, emergencies, soaring weather, soaring techniques, and cross-country flight is included. Topics such as radio navigation and communication, use of flight information publications, and regulations are available in other Federal Aviation Administration (FAA) publications.The discussion and explanations reflect the most commonly used practices and principles. Occasionally, the word “must” or similar language is used where the desired action is deemed critical. The use of such language is not intended to add to, interpret, or relieve a duty imposed by Title 14 of the Code of Federal Regulations (14 CFR). Persons working towards a glider rating are advised to review the references from the applicable practical test standards (FAA-G-8082-4, Sport Pilot and Flight Instructor with a Sport Pilot Rating Knowledge Test Guide, FAA-G-8082-5, Commercial Pilot Knowledge Test Guide, and FAA-G-8082-17, Recreational Pilot and Private Pilot Knowledge Test Guide). Resources for study include FAA-H-8083-25, Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-2, Risk Management Handbook, and Advisory Circular (AC) 00-6, Aviation Weather For Pilots and Flight Operations Personnel, AC 00-45, Aviation Weather Services, as these documents contain basic material not duplicated herein. All beginning applicants should refer to FAA-H-8083-25, Pilot’s Handbook of Aeronautical Knowledge, for study and basic library reference.It is essential for persons using this handbook to become familiar with and apply the pertinent parts of 14 CFR and the Aeronautical Information Manual (AIM). The AIM is available online at . The current Flight Standards Service airman training and testing material and learning statements for all airman certificates and ratings can be obtained from .This handbook supersedes FAA-H-8083-13, Glider Flying Handbook, dated 2003. Always select the latest edition of any publication and check the website for errata pages and listing of changes to FAA educational publications developed by the FAA’s Airman Testing Standards Branch, AFS-630.This handbook is available for download, in PDF format, from .This handbook is published by the United States Department of Transportation, Federal Aviation Administration, Airman Testing Standards Branch, AFS-630, P.O. Box 25082, Oklahoma City, OK 73125.Comments regarding this publication should be sent, in email form, to the following address:********************************************John M. AllenDirector, Flight Standards Serviceiiii vAcknowledgmentsThe Glider Flying Handbook was produced by the Federal Aviation Administration (FAA) with the assistance of Safety Research Corporation of America (SRCA). The FAA wishes to acknowledge the following contributors: Sue Telford of Telford Fishing & Hunting Services for images used in Chapter 1JerryZieba () for images used in Chapter 2Tim Mara () for images used in Chapters 2 and 12Uli Kremer of Alexander Schleicher GmbH & Co for images used in Chapter 2Richard Lancaster () for images and content used in Chapter 3Dave Nadler of Nadler & Associates for images used in Chapter 6Dave McConeghey for images used in Chapter 6John Brandon (www.raa.asn.au) for images and content used in Chapter 7Patrick Panzera () for images used in Chapter 8Jeff Haby (www.theweatherprediction) for images used in Chapter 8National Soaring Museum () for content used in Chapter 9Bill Elliot () for images used in Chapter 12.Tiffany Fidler for images used in Chapter 12.Additional appreciation is extended to the Soaring Society of America, Inc. (), the Soaring Safety Foundation, and Mr. Brad Temeyer and Mr. Bill Martin from the National Oceanic and Atmospheric Administration (NOAA) for their technical support and input.vv iPreface (iii)Acknowledgments (v)Table of Contents (vii)Chapter 1Gliders and Sailplanes ........................................1-1 Introduction....................................................................1-1 Gliders—The Early Years ..............................................1-2 Glider or Sailplane? .......................................................1-3 Glider Pilot Schools ......................................................1-4 14 CFR Part 141 Pilot Schools ...................................1-5 14 CFR Part 61 Instruction ........................................1-5 Glider Certificate Eligibility Requirements ...................1-5 Common Glider Concepts ..............................................1-6 Terminology...............................................................1-6 Converting Metric Distance to Feet ...........................1-6 Chapter 2Components and Systems .................................2-1 Introduction....................................................................2-1 Glider Design .................................................................2-2 The Fuselage ..................................................................2-4 Wings and Components .............................................2-4 Lift/Drag Devices ...........................................................2-5 Empennage .....................................................................2-6 Towhook Devices .......................................................2-7 Powerplant .....................................................................2-7 Self-Launching Gliders .............................................2-7 Sustainer Engines .......................................................2-8 Landing Gear .................................................................2-8 Wheel Brakes .............................................................2-8 Chapter 3Aerodynamics of Flight .......................................3-1 Introduction....................................................................3-1 Forces of Flight..............................................................3-2 Newton’s Third Law of Motion .................................3-2 Lift ..............................................................................3-2The Effects of Drag on a Glider .....................................3-3 Parasite Drag ..............................................................3-3 Form Drag ...............................................................3-3 Skin Friction Drag ..................................................3-3 Interference Drag ....................................................3-5 Total Drag...................................................................3-6 Wing Planform ...........................................................3-6 Elliptical Wing ........................................................3-6 Rectangular Wing ...................................................3-7 Tapered Wing .........................................................3-7 Swept-Forward Wing ..............................................3-7 Washout ..................................................................3-7 Glide Ratio .................................................................3-8 Aspect Ratio ............................................................3-9 Weight ........................................................................3-9 Thrust .........................................................................3-9 Three Axes of Rotation ..................................................3-9 Stability ........................................................................3-10 Flutter .......................................................................3-11 Lateral Stability ........................................................3-12 Turning Flight ..............................................................3-13 Load Factors .................................................................3-13 Radius of Turn ..........................................................3-14 Turn Coordination ....................................................3-15 Slips ..........................................................................3-15 Forward Slip .........................................................3-16 Sideslip .................................................................3-17 Spins .........................................................................3-17 Ground Effect ...............................................................3-19 Chapter 4Flight Instruments ...............................................4-1 Introduction....................................................................4-1 Pitot-Static Instruments ..................................................4-2 Impact and Static Pressure Lines................................4-2 Airspeed Indicator ......................................................4-2 The Effects of Altitude on the AirspeedIndicator..................................................................4-3 Types of Airspeed ...................................................4-3Table of ContentsviiAirspeed Indicator Markings ......................................4-5 Other Airspeed Limitations ........................................4-6 Altimeter .....................................................................4-6 Principles of Operation ...........................................4-6 Effect of Nonstandard Pressure andTemperature............................................................4-7 Setting the Altimeter (Kollsman Window) .............4-9 Types of Altitude ......................................................4-10 Variometer................................................................4-11 Total Energy System .............................................4-14 Netto .....................................................................4-14 Electronic Flight Computers ....................................4-15 Magnetic Compass .......................................................4-16 Yaw String ................................................................4-16 Inclinometer..............................................................4-16 Gyroscopic Instruments ...............................................4-17 G-Meter ........................................................................4-17 FLARM Collision Avoidance System .........................4-18 Chapter 5Glider Performance .............................................5-1 Introduction....................................................................5-1 Factors Affecting Performance ......................................5-2 High and Low Density Altitude Conditions ...........5-2 Atmospheric Pressure .............................................5-2 Altitude ...................................................................5-3 Temperature............................................................5-3 Wind ...........................................................................5-3 Weight ........................................................................5-5 Rate of Climb .................................................................5-7 Flight Manuals and Placards ..........................................5-8 Placards ......................................................................5-8 Performance Information ...........................................5-8 Glider Polars ...............................................................5-8 Weight and Balance Information .............................5-10 Limitations ...............................................................5-10 Weight and Balance .....................................................5-12 Center of Gravity ......................................................5-12 Problems Associated With CG Forward ofForward Limit .......................................................5-12 Problems Associated With CG Aft of Aft Limit ..5-13 Sample Weight and Balance Problems ....................5-13 Ballast ..........................................................................5-14 Chapter 6Preflight and Ground Operations .......................6-1 Introduction....................................................................6-1 Assembly and Storage Techniques ................................6-2 Trailering....................................................................6-3 Tiedown and Securing ................................................6-4Water Ballast ..............................................................6-4 Ground Handling........................................................6-4 Launch Equipment Inspection ....................................6-5 Glider Preflight Inspection .........................................6-6 Prelaunch Checklist ....................................................6-7 Glider Care .....................................................................6-7 Preventive Maintenance .............................................6-8 Chapter 7Launch and Recovery Procedures and Flight Maneuvers ............................................................7-1 Introduction....................................................................7-1 Aerotow Takeoff Procedures .........................................7-2 Signals ........................................................................7-2 Prelaunch Signals ....................................................7-2 Inflight Signals ........................................................7-3 Takeoff Procedures and Techniques ..........................7-3 Normal Assisted Takeoff............................................7-4 Unassisted Takeoff.....................................................7-5 Crosswind Takeoff .....................................................7-5 Assisted ...................................................................7-5 Unassisted...............................................................7-6 Aerotow Climb-Out ....................................................7-6 Aerotow Release.........................................................7-8 Slack Line ...................................................................7-9 Boxing the Wake ......................................................7-10 Ground Launch Takeoff Procedures ............................7-11 CG Hooks .................................................................7-11 Signals ......................................................................7-11 Prelaunch Signals (Winch/Automobile) ...............7-11 Inflight Signals ......................................................7-12 Tow Speeds ..............................................................7-12 Automobile Launch ..................................................7-14 Crosswind Takeoff and Climb .................................7-14 Normal Into-the-Wind Launch .................................7-15 Climb-Out and Release Procedures ..........................7-16 Self-Launch Takeoff Procedures ..............................7-17 Preparation and Engine Start ....................................7-17 Taxiing .....................................................................7-18 Pretakeoff Check ......................................................7-18 Normal Takeoff ........................................................7-19 Crosswind Takeoff ...................................................7-19 Climb-Out and Shutdown Procedures ......................7-19 Landing .....................................................................7-21 Gliderport/Airport Traffic Patterns and Operations .....7-22 Normal Approach and Landing ................................7-22 Crosswind Landing ..................................................7-25 Slips ..........................................................................7-25 Downwind Landing ..................................................7-27 After Landing and Securing .....................................7-27viiiPerformance Maneuvers ..............................................7-27 Straight Glides ..........................................................7-27 Turns.........................................................................7-28 Roll-In ...................................................................7-29 Roll-Out ................................................................7-30 Steep Turns ...........................................................7-31 Maneuvering at Minimum Controllable Airspeed ...7-31 Stall Recognition and Recovery ...............................7-32 Secondary Stalls ....................................................7-34 Accelerated Stalls .................................................7-34 Crossed-Control Stalls ..........................................7-35 Operating Airspeeds .....................................................7-36 Minimum Sink Airspeed ..........................................7-36 Best Glide Airspeed..................................................7-37 Speed to Fly ..............................................................7-37 Chapter 8Abnormal and Emergency Procedures .............8-1 Introduction....................................................................8-1 Porpoising ......................................................................8-2 Pilot-Induced Oscillations (PIOs) ..............................8-2 PIOs During Launch ...................................................8-2 Factors Influencing PIOs ........................................8-2 Improper Elevator Trim Setting ..............................8-3 Improper Wing Flaps Setting ..................................8-3 Pilot-Induced Roll Oscillations During Launch .........8-3 Pilot-Induced Yaw Oscillations During Launch ........8-4 Gust-Induced Oscillations ..............................................8-5 Vertical Gusts During High-Speed Cruise .................8-5 Pilot-Induced Pitch Oscillations During Landing ......8-6 Glider-Induced Oscillations ...........................................8-6 Pitch Influence of the Glider Towhook Position ........8-6 Self-Launching Glider Oscillations During Powered Flight ...........................................................8-7 Nosewheel Glider Oscillations During Launchesand Landings ..............................................................8-7 Tailwheel/Tailskid Equipped Glider Oscillations During Launches and Landings ..................................8-8 Aerotow Abnormal and Emergency Procedures ............8-8 Abnormal Procedures .................................................8-8 Towing Failures........................................................8-10 Tow Failure With Runway To Land and Stop ......8-11 Tow Failure Without Runway To Land BelowReturning Altitude ................................................8-11 Tow Failure Above Return to Runway Altitude ...8-11 Tow Failure Above 800' AGL ..............................8-12 Tow Failure Above Traffic Pattern Altitude .........8-13 Slack Line .................................................................8-13 Ground Launch Abnormal and Emergency Procedures ....................................................................8-14 Abnormal Procedures ...............................................8-14 Emergency Procedures .............................................8-14 Self-Launch Takeoff Emergency Procedures ..............8-15 Emergency Procedures .............................................8-15 Spiral Dives ..................................................................8-15 Spins .............................................................................8-15 Entry Phase ...............................................................8-17 Incipient Phase .........................................................8-17 Developed Phase ......................................................8-17 Recovery Phase ........................................................8-17 Off-Field Landing Procedures .....................................8-18 Afterlanding Off Field .............................................8-20 Off-Field Landing Without Injury ........................8-20 Off-Field Landing With Injury .............................8-20 System and Equipment Malfunctions ..........................8-20 Flight Instrument Malfunctions ................................8-20 Airspeed Indicator Malfunctions ..........................8-21 Altimeter Malfunctions .........................................8-21 Variometer Malfunctions ......................................8-21 Compass Malfunctions .........................................8-21 Glider Canopy Malfunctions ....................................8-21 Broken Glider Canopy ..........................................8-22 Frosted Glider Canopy ..........................................8-22 Water Ballast Malfunctions ......................................8-22 Retractable Landing Gear Malfunctions ..................8-22 Primary Flight Control Systems ...............................8-22 Elevator Malfunctions ..........................................8-22 Aileron Malfunctions ............................................8-23 Rudder Malfunctions ............................................8-24 Secondary Flight Controls Systems .........................8-24 Elevator Trim Malfunctions .................................8-24 Spoiler/Dive Brake Malfunctions .........................8-24 Miscellaneous Flight System Malfunctions .................8-25 Towhook Malfunctions ............................................8-25 Oxygen System Malfunctions ..................................8-25 Drogue Chute Malfunctions .....................................8-25 Self-Launching Gliders ................................................8-26 Self-Launching/Sustainer Glider Engine Failure During Takeoff or Climb ..........................................8-26 Inability to Restart a Self-Launching/SustainerGlider Engine While Airborne .................................8-27 Self-Launching Glider Propeller Malfunctions ........8-27 Self-Launching Glider Electrical System Malfunctions .............................................................8-27 In-flight Fire .............................................................8-28 Emergency Equipment and Survival Gear ...................8-28 Survival Gear Checklists ..........................................8-28 Food and Water ........................................................8-28ixClothing ....................................................................8-28 Communication ........................................................8-29 Navigation Equipment ..............................................8-29 Medical Equipment ..................................................8-29 Stowage ....................................................................8-30 Parachute ..................................................................8-30 Oxygen System Malfunctions ..................................8-30 Accident Prevention .....................................................8-30 Chapter 9Soaring Weather ..................................................9-1 Introduction....................................................................9-1 The Atmosphere .............................................................9-2 Composition ...............................................................9-2 Properties ....................................................................9-2 Temperature............................................................9-2 Density ....................................................................9-2 Pressure ...................................................................9-2 Standard Atmosphere .................................................9-3 Layers of the Atmosphere ..........................................9-4 Scale of Weather Events ................................................9-4 Thermal Soaring Weather ..............................................9-6 Thermal Shape and Structure .....................................9-6 Atmospheric Stability .................................................9-7 Air Masses Conducive to Thermal Soaring ...................9-9 Cloud Streets ..............................................................9-9 Thermal Waves...........................................................9-9 Thunderstorms..........................................................9-10 Lifted Index ..........................................................9-12 K-Index .................................................................9-12 Weather for Slope Soaring .......................................9-14 Mechanism for Wave Formation ..............................9-16 Lift Due to Convergence ..........................................9-19 Obtaining Weather Information ...................................9-21 Preflight Weather Briefing........................................9-21 Weather-ReIated Information ..................................9-21 Interpreting Weather Charts, Reports, andForecasts ......................................................................9-23 Graphic Weather Charts ...........................................9-23 Winds and Temperatures Aloft Forecast ..............9-23 Composite Moisture Stability Chart .....................9-24 Chapter 10Soaring Techniques ..........................................10-1 Introduction..................................................................10-1 Thermal Soaring ...........................................................10-2 Locating Thermals ....................................................10-2 Cumulus Clouds ...................................................10-2 Other Indicators of Thermals ................................10-3 Wind .....................................................................10-4 The Big Picture .....................................................10-5Entering a Thermal ..............................................10-5 Inside a Thermal.......................................................10-6 Bank Angle ...........................................................10-6 Speed .....................................................................10-6 Centering ...............................................................10-7 Collision Avoidance ................................................10-9 Exiting a Thermal .....................................................10-9 Atypical Thermals ..................................................10-10 Ridge/Slope Soaring ..................................................10-10 Traps ......................................................................10-10 Procedures for Safe Flying .....................................10-12 Bowls and Spurs .....................................................10-13 Slope Lift ................................................................10-13 Obstructions ...........................................................10-14 Tips and Techniques ...............................................10-15 Wave Soaring .............................................................10-16 Preflight Preparation ...............................................10-17 Getting Into the Wave ............................................10-18 Flying in the Wave .................................................10-20 Soaring Convergence Zones ...................................10-23 Combined Sources of Updrafts ..............................10-24 Chapter 11Cross-Country Soaring .....................................11-1 Introduction..................................................................11-1 Flight Preparation and Planning ...................................11-2 Personal and Special Equipment ..................................11-3 Navigation ....................................................................11-5 Using the Plotter .......................................................11-5 A Sample Cross-Country Flight ...............................11-5 Navigation Using GPS .............................................11-8 Cross-Country Techniques ...........................................11-9 Soaring Faster and Farther .........................................11-11 Height Bands ..........................................................11-11 Tips and Techniques ...............................................11-12 Special Situations .......................................................11-14 Course Deviations ..................................................11-14 Lost Procedures ......................................................11-14 Cross-Country Flight in a Self-Launching Glider .....11-15 High-Performance Glider Operations and Considerations ............................................................11-16 Glider Complexity ..................................................11-16 Water Ballast ..........................................................11-17 Cross-Country Flight Using Other Lift Sources ........11-17 Chapter 12Towing ................................................................12-1 Introduction..................................................................12-1 Equipment Inspections and Operational Checks .........12-2 Tow Hook ................................................................12-2 Schweizer Tow Hook ...........................................12-2x。

Analysis of heat exchange in the compensation chamber of a loop heat

Analysis of heat exchange in the compensation chamber of a loop heat pipeMariya A.Chernysheva*,Vladimir G.Pastukhov1,Yury F.Maydanik1Institute of Thermal Physics,Ural Branch of the Russian Academy of Sciences,Amundsena St.,106,Yekaterinburg620016,Russiaa r t i c l e i n f oArticle history:Received24August2012 Received in revised form18March2013Accepted1April2013 Available online13May2013Keywords:Loop heat pipeFlat evaporatorCompensation chamberHeat e and e mass transfer a b s t r a c tA three-dimensional heat e and e mass transfer model of aﬂat evaporator of a loop heat pipe has been developed for investigating heat e and e mass in a compensation chamberﬁlled with a liquid.Numerical simulation was implemented using EFDLabÒsoftware package in order to predict the temperature dis-tribution of theﬂat evaporator of a copper-water LHP(loop heat pipe)as well as theﬂow streamline and velocityﬁeld in the compensation chamber as a function of heat load.A computer simulation makes it possible to evaluate the heat exchange at the inner surface of the compensation chamber.Heat exchange data were used as a boundary condition in researching the problem of the drying effect of a wick and a transformation of the evaporating front in the active zone of theﬂat evaporator.Ó2013Elsevier Ltd.All rights reserved.1.IntroductionHPs(heat pipes)and LHPs(loop heat pipes)are two e phase heat e transfer devices operating on a closed evaporation e condensation cycle[1].The interest in HPs and LHPs is caused by a lot of practical problems connected with the thermal control and cooling of different equipment and devices.These devices are widely used in manyﬁelds of technology,such as the thermal management of space systems[2,3],utilization of solar energy [4,5],air conditioning[6],cooling systems of electronics[7e9],etc. In loop heat pipes,as distinct from heat pipes,the motion of vapor and liquid is organized through separate pipelines.Besides,in LHPs the capillary structure that creates the capillary head for pumping the workingﬂuid is located only in the heat e supply zone.There-fore,in LHPs use may be made ofﬁne e pored wicks,which create a higher capillary pressure,making it possible to increase consider-ably the heat e transfer capacity of the device.This means that it is possible to increase the heat e transfer length,and also the density of the heatﬂow delivered to the evaporator[10].One of the promising spheres of LHP application is energy e efﬁcient cooling systems of supercomputers[11].LHPs in super-computers may be used in combination with both an air and a water cooling system.Since the main heat sources in supercom-puters are the central and graphics processors dissipating up to150 and more watts,quite an urgent problem is the investigation and simulation of processes in the LHP evaporator at high heatﬂuxes.Among the numerous paper devoted to the investigation of loop heat pipes only a small part of them are devoted to theoretical analysis or numerical simulation of LHP evaporator,which is one of the most complicated elements of that heat e transfer device,and most of these papers present the results of investigations obtained on the basis of simpliﬁed models of the evaporator[12,13]or models that consider only a fragment of it[14,15].As a rule,this is a typical element of the evaporation zone including a single vapor e removal groove(at its cross e section),part of the wick and part of the evaporator body that are adjacent to this vapor e removal groove.One of theﬁrst publications with a detailed examination of heat e and e mass transfer in an LHP evaporator is a work by Fershtater[16].A certain part of the results of these investigations, namely,the results of numerical simulation of heat exchange in the compensation chamber e hydroaccumulator are presented in Refs.[17,18].In these publications the object of investigations is a cylindrical LHP evaporator with a uniform heat supply to its active zone.It should be noted that one of the advantages of the two e dimensional steady-state evaporator model developed in Ref.[16] is the fact that there the author examines the most complicated situation for simulation,at which the vapor phase of the working ﬂuid is present in the compensation chamber.*Corresponding author.Tel.:þ73432678791;fax:þ73432678799.E-mail addresses:maidanik@etel.ru,mariya@itp.uran.ru(M.A.Chernysheva). 1Tel.:73432678791;fax:73432678799.Contents lists available at SciVerse ScienceDirectEnergyjournal h omepage:w/locate/energy0360-5442/$e see front matterÓ2013Elsevier Ltd.All rights reserved./10.1016/j.energy.2013.04.014Energy55(2013)253e262Ref.[19]also presents a two e dimensional model of a cylindrical evaporator.Examined here is the case of steady e state operation of a loop heat pipe,at which the LHP had a vertical orientation with the evaporator located above the condenser.The authors investi-gated the effect of the natural convection and the value of heat load on the processes of the heat e and e mass transfer in the wick,the central core,and the compensation chamber.Loop heat pipes with ﬂat evaporators were developed later than LHPs with cylindrical evaporators [20e 23].Although interest in such developments is constantly increasing,it should be mentioned that the work on theoretical investigation of heat e and e mass transfer processes in ﬂat evaporators,as well as its detailed numerical simulation,has begun recently.Li and Peterson pre-sented a paper on 3D numerical analysis of heat transfer in the ﬂat square evaporator of an LHP with a fully saturated wick [24].They examined the operating conditions of an LHP with a ﬁlled compensation chamber.The authors focused their attention on heat e and e mass transfer in a wick,which according to their model was fully saturated with a liquid.The paper presets the results of simulation only for low heat loads.Besides,the authors ignored the heat e and e mass transfer processes in the compensation chamber and did not consider the problem of the effect of these processes on the heat transfer mechanism inside the LHP evaporator.A 3D steady e state model of a ﬂat LHP evaporator which ex-amines heat transfer in all the main elements of the evaporator,such as the body,wick,vapor e removal grooves,vapor collector,the barrier layer of the wick and the compensation chamber is presented in Ref.[25].The phenomenon of wick drying owing to the liquid boiling-up at high superheatings was taken into account in the problem.Such an approach made it possible to investigate changes in the wick saturation in the active zone of the evaporator with changes in the heat load and,besides,to simulate the trans-formation of the evaporating surface with the appearance of dried zones.The paper presets the results of calculations for a copperevaporator of a water LHP.It is also shown that this model may be used to calculate the thermal state of an evaporator at heat loads close to maximum ones,at which one can observe a heat transfer crisis in the ter this model was used for simulating heat transfer in a ﬂat evaporator of a copper e water LHP at different concentrations of the heat load supplied to the evaporator [26].Some details of the calculation procedure described in Refs.[25]and [26]have not been elucidated in full measure because they are signi ﬁcant enough in themselves and require a special consider-ation.Among them,in particular,is the problem of simulation of heat e exchange in the compensation chamber.This paper presents the results of investigating heat e and e mass transfer in the compensation chamber of a ﬂat evaporator of a copper e water LHP obtained with the use of the EFDLab Òsoftware package.It also suggests a method of calculation of the evaporator thermal state under changes in the saturation of the wick in which EFDLab simulation data of the heat exchange in the compensation chamber are used.2.Model of a ﬂat e oval evaporator for researching heat exchange in the compensation chamberThe compensation chamber is one of the main elements of the evaporator design,which in ﬂuence one another and in total determine the heat e and e mass transfer in the evaporator forming its thermal state.Since the compensation chamber is not an iso-lated object,for its detailed investigation it is necessary to consider heat e and e mass transfer processes in the whole evaporator.In the present paper the subject of investigation is a ﬂat-oval evaporator of a copper-water LHP,the results of experimental investigations of which are given in Ref.[27].Fig.1a shows the scheme of the evaporator of this LHP.The zone of heat load supply in loop heat pipes (or,as it is often called,the active zone)is in the evaporator part where the vapor e removal grooves are located.Theevaporatorputer model of ﬂat evaporator:a )e general view,b)e computational domain.M.A.Chernysheva et al./Energy 55(2013)253e 262254under investigation has twelve longitudinal grooves situated in the wick.They are positioned close to one of the ﬂat walls of the evaporator.Such a con ﬁguration of vapor-removal grooves pre-supposes a one e sided heat supply to the evaporator.Most of the heat supplied is expended in the evaporation of the liquid that saturates the wick.The vapor generated is removed through vapor-removal grooves into the vapor collector,and then from the evap-orator through a vapor line into the condenser.The cold liquid from the condenser returns into the evaporator through a liquid line.At ﬁrst it enters the compensation chamber.After that the liquid is absorbed through the butt e end surface of the wick,which faces the compensation chamber,and moves through the wick to the evap-oration zone.The problem considers the steady e state operation of a loop heat pipe with a uniform heat supply to the active zone of an evaporator.In the problem use was made of the following assumptions and suppositions.An LHP operates in the regime with a ﬁlled compensation chamber,that is,the vapor phase of the working ﬂuid is absent in it.Besides,no consideration is given to the liquid ﬁltration in the wick.This is caused by the potentialities of the EFDLab,which in such cases simulates a porous material as a solid body.Such an approach is quite acceptable at low ﬂow rates of the liquid passing through a porous body.Such is indeed the situation observed in the wick of a ﬂat evaporator of a loop heat pipe,the results of experimental investigations of which are reported in Ref.[27].The mass ﬂow rate of the working ﬂuid through the absorbing surface of the wick of this LHP is from 8.5Â10À6to 4.2Â10À4kg/s under changes in the heat load from 20to 1000W,the liquid velocity varying from 5.2Â10À5to 2.6Â10À3m/s.In conditions of a negligible convective heat-transfer component in a wetted (soaked with liquid)wick the heat transfer is mainly determined by its conductive component.For the characteristic of conductive heat transfer use is made of the effective thermal con-ductivity of a wick determined by:k eff ¼k w þε,k l ;(1)where εis the wick porosity,k l is he thermal conductivity of a liquid,and k w is he thermal conductivity of a porous material.It was estimated by the Odelevski ’s relation:k w ¼k comp ,À1ÀεÁ,ð1þεÞÀc ;(2)and k comp is the thermal conductivity of compact material.The index c is taken equal to 2.1.With allowance for the changes in k comp with temperature,the average value of the effective thermal conductivity of a copper wick with a porosity of 67%saturated with water for the temperature range corresponding to the operating temperatures of the LHP evaporator [27]is about 40W/m 2K.This value of k eff was used in the computer simulation.The next assumption used in simulating the evaporator con-cerns the ﬂow rate of the working ﬂuid in the wick.Since the heat losses from the evaporator into the outside ambient are insigni ﬁ-cant (they do not exceed 2%of the heat load supplied to the evaporator),they were not taken into account in calculating the ﬂow rate of the working ﬂuid G ,which in this case was determined as follows:G ¼Qh ÀT v Áþc p ,ÀT v ÀT lÁ;(3)where Q is the heat load,h is the evaporation heat,c p is the liquid heat capacity,T v is the vapor temperature in the evaporation zone and T l is the temperature of the liquid that enters the compensation chamber.The assumption was used in describing the boundaryconditions of the problem (see Table 2).It was also assumed that the temperature of the wick at the evaporating surface of the vapor-removal grooves was close to the vapor temperature in the grooves T v .This assumption made it possible to prescribe a boundary con-dition at the surface of the vapor e removal grooves.Under these assumptions,the governing equations for liquid in the compensa-tion chamber and the liquid line are as follows.The continuity equation:V ,V !¼0:(4)The momentum equation:r l V !V ,V ! ¼ÀV p þm l V 2V !þr l g !:(5)And the energy equation:r l c V !,V T¼k l V 2T :(6)For solid regions,such as the evaporator body,the wall of the liquid line and the wick,the energy equation is as follows:V 2T ¼0:(7)The simulation of heat e and e mass transfer processes in the evaporator was carried out with the help of the EFDLab software package,which realizes numerical solutions on the basis of the ﬁnite element method.The computer model took into account all the peculiarities of the evaporator design,which included a ﬂat e oval body,a wick with cylindrical vapor e removal grooves,a wick barrier layer,a compensation chamber and part of a liquid line inserted into the center of the compensation chamber in the form of a bayonet.The exit from the liquid line was located close to the absorbing surface of the wick,as shown in Fig.1a.The length of the external,with respect to the evaporator,calculation part of the liquid line was 100mm.Calculations were made for the real ge-ometry of an evaporator similar in size and con ﬁguration to the evaporator of an experimental LHP [27].The main design param-eters of this evaporator are presented in Table 1.In considering a three e dimensional problem the symmetry of the object under investigation about the 0YZ plane was taken into account.This made it possible to reduce the computational effort.The computational domain is presented in Fig.1b.Shown here is also the calculation grid at the longitudinal section of the evapo-rator.It is supplemented by two cross e sections situated in theTable 1The main parameters of the ﬂat evaporator.EvaporatorTotal length,mm 80Width,mm 42Thickness,mm7Case thickness,mm0.5Compensation chamber length,mm 40Vapor-removal grooves Number 12Length,mm 32Diameter,mm 1.8WickWick length,mm 40Porosity,%67Breakdown pore radius,m m 21Heating zone Length,mm 30Width,mm 30Active zone Length,mm 32Width,mm42M.A.Chernysheva et al./Energy 55(2013)253e 262255region of the heating zone and the compensation chamber.It is seen that the calculation grid used is nonuniform in space co-ordinates.Such a con ﬁguration of the calculation grid was chosen for a more precise description of the investigated object,and also for more complete conformity the model to the peculiarities of the problem in simulating real physical processes in the evaporator.In particular,a higher density of the cells was prescribed in the re-gions where large gradients of physical parameters could be observed.First of all,this refers to the heating zone with the vapor e removal grooves and the compensation chamber.The total number of cells in the calculation grid was about 140thousand.The boundary conditions of the evaporator model are presented in Table 2.In simulating the effect of the gravity force on the liquid ﬂow in the compensation chamber was taken into account (Eq.(5)).Calculations have been made for two orientations of the evaporator.In the ﬁrst case the evaporator was located horizontally (4¼0 )and the heat load was supplied from below.With the other orientation the evaporator was positioned vertically (4¼90 ),and the compensation chamber was above.In numerical simulation the range of changes in the heat load supplied to the evaporator was from 20to 500W.The vapor tem-perature T v varied in the temperature range from 50to 70 S ,which is topical for two e phase heat e transfer devices used for cooling of electronics.The heat exchange at the outer surface of the evaporator and the liquid line was prescribed according to the condition #5of Table 2.In calculations the ambient temperature T amb was 20 S ,and the value of the external heat e transfer coef ﬁcient a amb was taken equal to 5W/K m 2.The liquid at the entrance into the liquid line had a temperature of 20 S .The numerical results based on developed model are presented in the following section.3.Results and discussion3.1.Temperature distribution in evaporatorA series of numerical calculations of the temperature distribu-tion in a ﬂat e oval evaporator of a copper e water LHP has been carried out.As an example Fig.2shows the variation of temperature on the lower wall of the evaporator,to which heat is supplied,and also at two perpendicular sections.One of them,the YZ section,passes along the symmetry line of the evaporator.In the second case this is the XY plane,which dissects the evaporator at the point with a coordinate along the Z -axis corresponding to the middle of the length of the vapor e removal grooves.Fig.2shows the variation of the thermal state of the evaporator at the horizontal orientation (4¼0 )with heat load.The temperature at the evaporating surfaceof the wick at all heat loads was set equal to 60 C.It is seen that an increase in the heat load leads to an increase in the temperature gradient along the evaporator.The increase of temperature in-homogeneity is caused by two factors.The ﬁrst is the temperature rise with increasing heat load of the evaporator part that is close to the heating zone,and this process,as such,is quite predictable.The highest temperature rise is observed on the evaporator wall under the heat source.The other factor that in ﬂuences the increase of temperature inhomogeneity is the temperature decrease on the opposite side of the evaporator,where the compensation chamber is situated.The reason for this is the increasing ﬂow rate of the liquid arriving at the chamber with an increase in heat load.Augmented portions of a cold working ﬂuid are not only capable of compen-sating for the heat ﬂows from the heating zone into the compen-sation chamber caused by the conductive heat transfer over the wick and the body,which also increase with increasing heat load,but can also lower the temperature of the compensation chamber.As a result,with increasing heat load one can observe the reverse tendency for temperature change on the opposite parts of the evaporator,i.e.a temperature increase in the heating zone and its decrease in the compensation chamber (see Fig.2).3.2.Analysis of the results for the compensation chamber3.2.1.Effect of the gravity force and the evaporator orientation on the ﬂow ﬁeldA preliminary analysis of the results of simulation has shown that the allowance for the gravity forces is necessary as their actionTable 2The boundary conditions for an EFDLab model of the ﬂat evaporator.RegionBoundary conditions 1Heating zoneQ ¼const,q ¼Q /S h 2Surface of vapor-removal groovesT y T v ,T v ¼const3Wick absorbing surfaceMass ﬂow rate of working ﬂuid:G out ¼Q =Àh ÀT v Áþc p ,ÀT v ÀT lÁÁ4Entrance into liquid lineLiquid temperature:T l ¼const.Pressure:P ¼P s (T v ).Mass ﬂow rate of working ﬂuid:G in ¼G out5Outer surface of evaporator and liquid lineq ¼a amb ,ðT b ÀT amb Þ6Butt-end surface of wick turned into vapor collectorv T /v z ¼Fig.2.Temperature distribution in the evaporator for 4¼0 at different heat loads:e 100W;b)e 300W;s )e 500W.M.A.Chernysheva et al./Energy 55(2013)253e 262256leads to the appearance of additional convective liquid ﬂows in the compensation chamber,which make the ﬂow pattern more complicated.Changes of this kind,in the long run,affect the in-tensity of heat e exchange processes in the compensation chamber.With all this taken into consideration,the results of numerical calculations presented have been obtained with allowance for the action of the gravity forces.Figs.3and 4illustrate the lines of the liquid current in the compensation chamber at the horizontal and theverticalFig.3.Liquid current lines in compensation chamber at 4¼0 and different heat loads:a )e 100W,b)e 300W,c)e 500W.Fig.4.Liquid current lines in compensation chamber for 4¼90 and at different heat loads:a )e 100W,b)e 300W,c)e 500W.M.A.Chernysheva et al./Energy 55(2013)253e 262257orientation in the evaporator,respectively.Data are presented for three values of heat loads:100,300and500W.The temperature of the evaporating surface of the wick is60 C.It is seen that changes in the evaporator orientation have a considerable effect on the pattern of the liquid current in the chamber.Thus,at the horizontal orientation of the evaporator(4¼0 )in the compensation cham-ber there are ring e shapedﬂows both at the longitudinal direction and at the transverse direction.It may also be noted that at all heat loads in the butt e end part of the compensation chamber there is a stagnant zone,in which free e convective annularﬂows are domi-nant.At the vertical orientation(4¼90 )theﬂow becomes more ordered.Thus,for instance,at a heat load of100W one can observe a well e deﬁned large e scale circularﬂow formed under the effect of free convection,which embraces the whole compensation cham-ber.It has an ascending direction at the peripheral wall and a descending one in the central part near the bayonet tube.Theﬂow rate of the workingﬂuid coming from the liquid line increases with increasing heat load.An increase in the velocity of the liquid ﬂowing from the bayonet into the compensation chamber leads to the turbulization of theﬂow,and in the place of a large circular vortex there form several smaller vortex structures.3.2.2.Analysis of velocityﬁeldFig.5shows a velocityﬁeld in the compensation chamber at the horizontal orientations of the evaporator.At the exit from the bayonet the liquid has a considerable velocity.When the working ﬂuid is injected into the compensation chamber,its motion is retarded.It can be seen that the velocity of the liquid decreases rapidly as it moves away from the“point”of the liquid injection in the chamber.According to the results of calculations,in the whole heat e load range investigated there is a small region,located be-tween the end of the bayonet outlet and the wick,where the liquid has a high velocity.The rest of the compensation chamber is occupied with a slow e moving liquid.The stagnant zone is situated here.With increasing heat load the region with a more intense liquid motion increases.However,the data obtained show that even at high heat loads a large part of liquid in the compensation chamber has a small velocity of travel and a weak convective stir-ring.At the horizontal evaporator orientation one can observe a similar pattern of changes in the velocityﬁeld under changes in the heat load.3.2.3.Local and average heat exchange characteristicsFig.6shows changes in the heat exchange intensity at the inner surface of the compensation chamber with increasing heat load.The results are presented for the lower wall of the compensation chamber and are used as an example.It is seen that the heat e ex-change coefﬁcient has the highest values close to the exit from the bayonet tube.In this rejoin,according to Fig.5,the liquid has the highest velocity,and theﬂow a high vorticity(Fig.3).On the opposite side of the compensation chamber,where the stagnant zone with a slow-movingﬂow is located,a weak heat exchange is observed.An increase in the massﬂow rate of the forkingﬂuid caused by increasing heat load results in intensiﬁcation of the heat e exchange processes,but,according to the data obtained,this takes place not everywhere,but only in the region adjacent to the absorbing surface of the wick,through which the liquid was sucked from the chamber into the wick.To all appearances,it is precisely this circumstance,i.e.a close disposition of the bayonet outlet and the absorbing surface of the wick,that contributes to the fact that only a local intensiﬁcation of heat exchange takes place here.The corresponding data on the intensity of heat e exchange at other inner surface of the compensation chamber and at other vapor temperatures have also been obtained.They have shown that at all lateral surfaces one can observe a similar character of changes in heat exchange,and a similar tendency of changes in heat e ex-change intensity with increasing heat load.For the generalization of the obtained results characterizing the local heat exchange in-tensity,and also for the subsequent use and analysis of these re-sults,calculations have been made of the mean(with respect to the whole inner surface of the compensation chamber)values of the heat e exchange coefﬁcients.Fig.7presents their heat load de-pendences for the evaporator horizontal orientation at different vapor temperatures T v in the evaporation zone.It is seen that in the range of low heat loads the values of the heat e exchange co-efﬁcients practically coincide,and at high Q the calculated points for different vapor temperatures are situated sufﬁciently close to each other.And,nevertheless,the following regularity is observed: the heat e exchange coefﬁcients increase with increasing vapor temperature T v.The increase of the heat-exchange intensity in the compensa-tion chamber with increasing T v may be caused by two reasons.The ﬁrst is connected with decreasing liquid viscosity in the compen-sation chamber.The fact is that an increase of the temperature in the evaporation zone is accompanied by an increase inthe Fig.5.Liquid velocityﬁeld in compensation chamber at4¼0 and different heat loads:a)e100W,b)e300W,c)e500W.M.A.Chernysheva et al./Energy55(2013)253e262 258temperature of the whole evaporator,including the temperature of the compensation chamber.When heated,the liquid becomes less viscous,and this contributes to the intensi ﬁcation of convection motion in the compensation chamber.A more intense mixing of the working ﬂuid leads in the long run to the increase of the internal heat e exchange.Another reason for the heat-exchange enhance-ment is the increase in the velocity of the liquid that arrives fromthe bayonet into the compensation chamber owing to the increase of the working ﬂuid ﬂow rate depending,according to the condi-tion #3in Table 2,on the heat of evaporation,which decreases with increasing temperature.As was shown earlier (Section 3.2.2),an increase in the velocity of the working ﬂuid arriving in the compensation chamber leads to an acceleration of the liquid ﬂows circulated inside the chamber and a more intense liquid stirring.Since in the vapor temperature range investigated one can observe a rather weak temperature dependence of the heat e ex-change intensity,it is possible to average the heat e exchange co-ef ﬁcients over the parameter T v .Fig.8presents the average values of the coef ﬁcients a cc depending on the heat load for the horizontal orientation of the evaporator.An analysis has shown that the re-sults presented here can be interpolated with an accuracy of Æ7%by the linear dependence:a ss ðQ Þ¼A ,Q þB(8)with the following values of the coef ﬁcients of linear interpolation:A ¼0.2945and B ¼1.9869.Similar calculations at the same heat loads and temperatures have been made for the vertical orientation of the evaporator.On the basis of the data obtained an interpolation dependence of type (8)with the coef ﬁcient values A ¼0.215and B ¼8.6347has been obtained.Both interpolation lines are presented in Fig.8.It may also be noted that the heat load dependences of the heat-exchange coef ﬁcients presented in Fig.7have a smooth form.Such a character of changes in the coef ﬁcients presupposes the possi-bility of extrapolation of the data obtained to a region of higherheatFig.6.Heat-exchange coef ﬁcient ﬁeld for 4¼0 at different heat loads:a )e 100W,b)e 300W,c)e 500W.Fig.7.Heat load dependence of the heat-exchange at different vapor temperatures:C e 50 S ,-e 60 S ,:e 70 S.Fig.8.Heat load dependence of the mean heat exchange coef ﬁcient at 4¼0 and 4¼90 orientation of evaporator:B C e calculation data,d e e e linear interpolation.M.A.Chernysheva et al./Energy 55(2013)253e 262259。

欧司朗热风工具说明书

HOT AIR TOOL 3500068462, 068463, 068464, 070878, 071383⇒ FOR SAFETY AND LONG HEATER LIFE, CAREFULLY READ THIS MANUAL BEFORE USE.Description!Compact, efficient heater with stainless steel housing and positive hose-barb air connection for heating air or inert gases to 1400°F (760°C). Built in “K” Thermocouple allows for closed-loop control of temperature to ±1°F of set point. If operated correctly, the heater will operate continuously for 5000 hours or longer.SpecificationsMAXIMUM INLET PRESSURE 60 PSI (4 BAR)MAXIMUM INLET AIR TEMPERATURE 120°F (50°C)MAXIMUM EXIT AIR TEMPERATURE 1400°F (760°C)MODEL NUMBERMAXIMUM WATTAGEMAXIMUM VOLTAGEAMP RATINGMINIMUM INLET PRESSURE PSI (mBAR)MINIMUM FLOW SCFH(SLPM)0684621500120130.3 (21)30 (14)068463200024090.6 (41)70 (33)068464350024015 1.0 (70)90 (43)Safety!SHOCK HAZARD Only qualified individuals should install this heater and related controls. Follow all applicable electrical codes and use proper wiring.! BURN/FIRE/EXPLOSION HAZARD Do not use with or near explosive or reactive gases. Avoidcontact with the side, or exposure to the exit-end, during or soon after operation. DO NOT USE NEAR VOLATILE OR COMBUSTIBLE MATERIALS.Precautions!Use filtered air. Avoid grease, oil, or oil vapors, corrosive or reactive gases which will damage heater.!Operate at safe voltages as shown on the PERFORMANCE CURVES. Excess voltage will cause premature failure.!Always have sufficient airflow through the heater before applying power. Otherwise element will overheat very quickly, and burn out. NOTE: A thermocouple cannot detect temperatures if there is no flow – turn on flow before applying power, even when a controller with a thermocouple is being used. !Use phase angle fired power controllers. On-off controllers may shorten heater life (or burnout element).!For closed-loop control, use a temperature controller with a fast sampling period (500ms) and minimal overshoot.Installation"Securely mount the heater. Do not clamp so tightly as to distort the stainless steel housing. "Connect the filtered air source to the heater using ¼” ID high pressure tubing."Connect the two power leads, grounding screw, and thermocouple leads to the appropriate connections. For “K” thermocouples, the red lead is negative (-), and the yellow lead is positive (+). "If a thermocouple is used, ensure that it is located within one inch from the heater exit.Start-up"Reference the PERFORMANCE CURVES section for operational parameters before attempting to operate heater(s)."Turn on air supply and adjust to desired flow/pressure."If using a closed loop system, turn on power to the temperature and power controller, then set the desired temperature on the temperature controller. If using an open loop system, increase power to the heater through the power controller until the desired temperature is attained.Performance CurvesTo use these curves, first determine the pressure at the heater entrance or flow through the heater, and then locate the maximum allowable temperature on the curve. DO NOT EXCEED THAT TEMPERATURE. If you are not using a closed-loop control, The second set of performance curves show the maximum voltage that may be applied to these heaters as a function of air pressure. The pressure is the pressure at the heater entrance with no bends, elbows, or tube ID restrictions between the pressure gauge and the heater.WarrantyOSRAM SYLVANIA warrants that all products to be delivered hereunder will be free from defects in material and workmanship at the time of delivery. OSRAM SYLVANIA's obligation under this warranty shall be limited to (at its option) repairing, replacing, or granting a credit at the prices invoiced at the time of shipment for any of said products. This warranty shall not apply to any such products which shall have been repaired or altered, except by OSRAM SYLVANIA, or which shall have been subjected. OSRAM SYLVANIA shall be liable under this warranty only if (A) OSRAM SYLVANIA receives notice of the alleged defect within sixty (60) days after the date of shipment; (B) the adjustment procedure hereinafter provided is followed, and (C) such products are, to OSRAM SYLVANIA’s satisfaction, determined to be defective.THE WARRANTY SET FORTH IN THE PRECEDING PARAGRAPH IS EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE OR OF MERCHANTABILITY.The information contained in this manual is based on data considered to be true and accurate. Reasonable precautions for accuracy has been taken in the preparation of this manual, however OSRAM SYLVANIA assumes no responsibility for any omissions or errors, nor assumes any liability for damages that may result from the use of the product in accordance with the information contained in this manual. Please direct all warranty/repair requests or inquiries to the place of purchase, and provide the following information, in writing:(A)Order number under which products were shipped(B)Model/Serial Number of product(C)Reason for rejectionPRODUCTS CAN NOT BE RETURNED TO OSRAM SYLVANIA WITHOUT AUTHORIZATION. Replacement, repair, or credit for products found to be defective will be made by the place of purchase. All products found to be not defective will be returned to the Buyer; transportation charges collect or stored at Buyers expense.。

Flotherm热管建模方法

Analysis of a Heat Pipe Assisted Heat SinkJohn ThayerThermacore International780 Eden RoadLancaster, PA 17604-3234Tel: 717-569-6551 x208John.Thayer@IntroductionHeat pipes can be useful in improving the performance of heat sinks in electronics cooling applications. As phase change heat transfer devices, heat pipes very effectively transfer heat over their length with only a small temperature gradient. Heat pipes are commonly available in two form factors; cylindrical heat pipes that transfer heat in 1 dimension, and vapor chambers (flat heat pipes) that transfer heat in 2 dimensions. When used in high heat flux applications where conduction losses are significant, heat pipes can reduce component temperatures by 10-20C. This paper reports on the analytical and experimental results of such an application. A heat sink for a high power forced convection telecom cooling application was optimized using Flotherm CFD modeling. Three design options were considered; plain aluminum base, an aluminum base with 3 cylindrical heat pipes embedded in machined grooves, and a vapor chamber base. All options used the same folded fin stack. The Flotherm analysis accurately predicted the benefit of using heat pipes for minimizing spreading resistance in the base of the heat sink. Table 1 gives the comparison between analytical and experimental results.Table 1Description of the Heat SinkThe heat sink had a base of 150 mm in the flow direction and 215 mm across the flow. The base was 8 mm thick. The fin stack was folded fin of 0.6 mm thickness, 1.6 mm pitch, and 18 mm height. The fins extended only 76 mm in length, covering less than half the base length. The base was alloy 6063 and the fins were alloy 1100. The fins and base were nickel plated and soldered together.Two heat sources, listed in Table 2, were bolted to the base, with a layer of thermal interface material in between. Table 2Heat Source Size (mm)Power (W)Flux (W/cm2) Major25 x 9.58435 Minor19 x 6.4119 Heat Sink Design Model Test Ratio Plain Base0.390.36110% Embedded Heat Pipe0.300.29103% Vapor Chamber0.240.24103%ΘHS-A (C/W)The design airflow was 30 m3/hr at 30 Pa pressure drop. The heat sink is intended to be mounted on a circuit board and installed in a card cage at a 30 mm board pitch.Initial calculations showed that spreading resistance in the base was the dominant portion of the overall thermal resistance, 20 C out of an estimated total of 35 C. Thus the heat sink was an excellent candidate forheat pipe augmentation. As mentioned, 3 designs were under consideration; plain aluminum base, an aluminum base with 3 cylindrical heat pipes embedded in machined grooves, and a vapor chamber base. The embedded heat pipes were 0.25” diameter copper/water heat pipes of varying lengths, formed into curved shapes that fit within the restricted areas of the heat sink base but extended to spread the heat to the far corners of the sink. The pipes were pressed into round bottom grooves and flattened on top to be coplanar with the base surface. They were soldered in place. The copper vapor chamber was mounted in an aluminum frame and extended to the area underneath the fin. Figures 1 and 2 show top and bottom views of the heat sink.Figure 1 – Heat Sink fin stack Figure 2 – Heat Sink Base with Embedded Heat PipesFlotherm ModelTo evaluate the performance gain available from a heat pipe heat sink design, Flotherm models were constructed of all 3 designs. In general heat pipes can be modeled with 4 elements:•Copper walls+Cuboid with the externaldimension of heat pipe.+k = 380 W/mK•Vapor space+Cuboid with the internaldimension of the hollow space.+k = 50000 W/mK•Wick+Collapsed cuboid at the interface between the Cu wall and thevapor space & thickness of 1 mm +k = 40 W/mK•Interface+Collapsed cuboid at the interface between the Cu wall and thesurrounding solid & thickness ofthe interface material.+k = appropriate for contactresistance.This modeling scheme captures the main aspects of heat pipe heat transfer. In particular the high conductivity vapor space allows heat to flow with virtually no temperature gradient along the entire length of the heat pipe. It captures the wick resistance as the primary component of overall thermal resistance of the heat pipe itself. It allows the possibility of spreading in the copper walls. And any thermal interface between the heat pipe and other model elements can be included.While vapor chambers often have significant spreading in their walls, embedded heat pipes usually have negligible lateral spreading. There is little to be gained by making the walls cuboid elements with 3 dimensional conduction. The modeling scheme was simplified for the embedded heat pipe model by lumping the copper wall, wick and interface into one collapsed cuboid element with 1 dimensional heat flow. The effective conductivity would represent the resistance to heat flow of all three layers. This also has the beneficial effect of eliminating very thin cells required to represent the walls.•Copper walls, wick & interface.+Envelope of collapsed cuboidswith the external dimension of theheat pipe.+k = effective for 3 layers (usually dominated by the interface)•Vapor space+Cuboid with the externaldimension of the heat pipe.+k = 50000 W/mKIt is important to note that this modeling scheme does NOT model the physics of phase change heat transfer. Artifices are used to represent two major factors in heat pipe heat transfer. While conduction in a super high conductivity cuboid may have low gradients, it does not model vapor flow, the associated pressure gradient and consequent temperature gradient. The temperature gradient associated with the boiling of fluid at the heat source is only represented in a coarse fashion as a constant conductive resistance of a collapsed cuboid. None of the nuances such as dependence on heat flux, wick structure, etc., are captured. The value of conductivity for the wick of 40 W/mK is a conservative value suitable for typical sintered copper powder wicks and relatively low heat fluxes of below 50 W/cm2.It is also important to note that this modeling scheme does NOT model the real limits to maximum heat flow imposed by such factors as viscous losses in the return flow of condensate in the wick. It is quite possible to analytically achieve unrealistically high heat flow in such a model. A complete heat pipe design analysis would include a separate evaluation of the maximum power capability.Because all three base designs used the same fin stack, the airflow side of the Flotherm model needed to be solved only once. Since this was the most time consuming part of the number crunching, this tactic was used. To facilitate this all the heat pipe model elements were included in the same overall model (thus using the same grid and hence same flow field). For the thermal solution the appropriate heat pipe elements were turned on or off and a “Freeze Flow” thermal solution was recomputed for each different design.Figures 3, 4 & 5 show the geometry of the heat sink and heat pipe model. Figure 3 - Heat Sink OutlineFigure 4 - Embedded Heat Pipe Layout (Note that the Flotherm analysis and matching experimental data was of an earlier design rev than that shown in the photo of Figure 2)Figure 5 - Vapor Chamber LayoutResultsFigure 6 - Plain Base Results Temperature ContoursFigure 7 - Embedded Heat Pipe Results Temperature ContoursFigure 8 - Vapor Chamber Results Temperature ContoursThe Flotherm results predicted a 23% improvement in heat sink thermal resistance for the embedded heat pipe version and a 38% improvement for the vapor chamber version. Based on these predictions it was deemed that sufficient gain was available to warrant the fabrication of prototype heat sinks.The prototypes were tested in a channel flow test fixture that matched the dimensions and flow conditions of the card cage. There was an excellent match between the Flotherm results and experimental data, as shown in Table 1and Chart 3.Chart 3 – Experimental & Analytical Results ComparisonFor the current power level of 84 W, the heat pipe and vapor chamber designs offered 5.5 C and 10 C component temperature reductions respectively. As the power dissipation for the design rises to the expected 150 W level, the improvement will be on the order of 20 C, making the heat pipe a make-or-break cooling technology for this design. Experimental error is on the order of +/-10%, due primarily to thermocouple error and parasitic power loss from the heater. Analytical error is on the order of +/- 20%, primarily due to the simplification used for modeling wick resistance. Chart 4 shows with experimental data that rather than being a constant value, as assumed, heat sink resistance varies with power (due to wick resistance heat flux dependency). Unfortunately Flotherm cannot vary material conductivity (the modeling mechanism for wick resistance) by heat flux. In addition, there are the usual CFD error sources, primarily grid refinement near the heat source and in the boundary layer of the fins. Because of the large number of fins, only a coarse grid of 2 cells between each fin could be solved. Even still the total grid size was590000 cells.Vapor Chamber Heat Sink Performance11 W to Secondary Heat Source050100150200250300Amplifier Power (W)ThermalResistance(C/W)Chart 4 – Heat Sink Resistance vs PowerConclusionThe heat transfer effects of heat pipes in electronic cooling applications can be modeled with reasonable accuracy in Flotherm. This allows the thermal engineer to asses the potential benefit of adding heat pipes to a design in a timely and cost efficient manner. This would include early stage feasibility studies as well as design optimization in a later, prototype design stage.。

Parametric analysis of loop heat pipe operation a literature review

International Journal of Thermal Sciences 46(2007)621–636/locate/ijtsParametric analysis of loop heat pipe operation:a literature reviewStéphane Launay 1,Valérie Sartre 2,Jocelyn Bonjour ∗Centre de Thermique UMR 5008CNRS-INSA-UniversitéLyon 1,Institut National des Sciences Appliquées,Bât.Sadi Carnot,9rue de la Physique,69621Villeurbanne cedex,FranceReceived 25July 2006;received in revised form 30October 2006;accepted 10November 2006Available online 20December 2006AbstractLoop heat pipes (LHPs)are heat transfer devices whose operating principle is based on the evaporation/condensation of a working ﬂuid,and which use the capillary pumping forces to ensure the ﬂuid circulation.Their major advantages as compared to heat pipes are an ability to operate against gravity and a greater maximum heat transport capability.In this paper,a literature review is carried out in order to investigate how various parameters affect the LHP operational characteristics.This review is based on the most recent published experimental and theoretical studies.After a reminder of the LHP operating principle and thermodynamic cycle,their operating limits are described.The LHP thermal resistance and maximum heat transfer capability are affected by the choice of the working ﬂuid,the ﬁll charge ratio,the porous wick geometry and thermal properties,the sink and ambient temperature levels,the design of the evaporator and compensation chamber,the elevation and tilt,the presence of non-condensable gases,the pressure drops of the ﬂuid along the loop.The overall objective for this paper is to point the state-of-the-art for the related technology for future design and applications,where the constraints related to the LHPs are detailed and discussed.©2006Elsevier Masson SAS.All rights reserved.RésuméLes boucles diphasiques àpompage capillaire sont des systèmes dont le principe de fonctionnement est basésur l’évaporation/condensation d’un ﬂuide et qui utilisent les forces de capillaritépour faire circuler le ﬂuide dans la boucle.En comparaison des caloducs,les principaux avantages des boucles diphasiques àpompage capillaire sont une aptitude àvaincre les forces de gravité,lorsque le système est en position défavorable,et une puissance maximale transférable supé présente étude bibliographique,basée sur les travaux expérimentaux et théoriques les plus récents,a pour but est de comprendre comment différents paramètres inﬂuencent le comportement de la boucle.Après un rappel du principe de fonctionnement et du cycle thermodynamique de la pompe,ses limites de fonctionnement sont décrites.Sa résistance thermique et sa puissance maximale transférable dépendent du choix du ﬂuide de travail,du taux de remplissage,de la géométrie et des propriétés thermophysiques de la structure capillaire,de la température ambiante,de la température de la source froide,de la géométrie de l’évaporateur et de la chambre de compensation,de l’élévation et l’inclinaison du système,de la présence de gaz incondensables et des pertes de pression du ﬂuide le long de la boucle.L’objectif de cet article est de présenter l’état de l’art relatif aux inﬂuences de divers paramètres sur le fonctionnement des LHPs.©2006Elsevier Masson SAS.All rights reserved.Keywords:Loop heat pipe;Effect of gravity;Wick characteristics;Working ﬂuid;Fluid charge;Pressure drops;Ambient temperature;Heat sink temperature;Design Mots-clés :Boucle diphasique àpompage capillaire ;Gravité;Caractéristiques du milieu poreux ;Fluide ;Charge ;Chutes de pression ;Température ambiante ;Température de la source froide ;Géométrie*Corresponding author.Tel.:+33(0)472436427;fax:+33(0)472438811.E-mail addresses:unay@insa-lyon.fr (unay),valerie.sartre@insa-lyon.fr (V .Sartre),jocelyn.bonjour@insa-lyon.fr (J.Bonjour).1Tel.:+33(0)472438491;fax:+33(0)472438811.2Tel.:+33(0)472438166;fax:+33(0)472438811.1290-0729/$–see front matter ©2006Elsevier Masson SAS.All rights reserved.doi:10.1016/j.ijthermalsci.2006.11.007unay et al./International Journal of Thermal Sciences46(2007)621–636Contents1.Introduction (622)2.LHP theory (623)2.1.LHP description (623)2.2.LHP operating principles (624)2.3.Thermodynamic analysis (624)2.4.LHP operating limits (625)2.4.1.Viscous limit (625)2.4.2.Sonic limit (625)2.4.3.Entrainment limit (625)2.4.4.Capillary limit (625)2.4.5.Boiling limit (625)3.LHP parametric study (626)3.1.Effect ofﬂuid charge (626)3.2.Effect of the porous wick characteristics and of the groove design (627)3.3.Effect of the workingﬂuid (629)3.4.Effect of non-condensable gases (630)3.5.Effect of the gravity(elevation and tilt) (630)3.6.Effect of the evaporator/reservoir design on the heat leak (632)3.7.Effect of pressure drops (633)3.8.Effect of sink and ambient temperatures (633)4.Conclusions (635)References (635)1.IntroductionIn theﬁeld of electronic industry,the component devel-opment is conducted by the increase in performance and the miniaturization of electronic systems,resulting in an increase of the heat dissipation.To insure a high reliability of the com-ponent,which is closely dependent on its temperature level, the thermal management of electronics becomes a major chal-lenge.As conduction or air convection cooling systems are no more efﬁcient to transfer such high heatﬂuxes,alterna-tive cooling techniques have to be used.Among the available techniques,two-phase capillary thermal control devices such as Heat Pipes(HP),Micro Heat Pipes(MHP),Capillary Pumped Loops(CPL),and Loop Heat Pipes(LHP)are specially promis-ing.They are self-circulating devices where heat is removed by phase change and the workingﬂuid is circulated by ther-modynamic forces.Theﬁrst heat pipe was conceived as a “Perkins tube”in1892.Theﬁrst CPL was invented by Stenger, whose results where published in1966.The LHP was devel-oped and tested in1972in the former Soviet Union[1].The development of LHPs was a response to the challenge of the increasing needs of electronic systems,and with the speciﬁc de-mand of aerospace technology,which requires high operational reliability and robustness[2–10].The two-phase loops offer many advantages over heat pipes[1,11]in terms of operation against gravity,maximum heat transport capability,smooth-walledﬂexible transport lines,and fast diode action.The basic distinction between a conventional CPL and a con-ventional LHP lies in theﬂuidic and thermal links of the com-pensation chamber to the evaporator.This distinction has a large impact on the design and operation of the capillary loop[12, 13].The physical proximity of the reservoir to the evaporator,which are connected by the use of a secondary wick,simpliﬁes the LHP start-up and makes the LHP operation vapour-tolerant. Both contribute to the robustness of the LHP operation under various conditions.The preconditions required for a CPL is a major disadvantage that makes the LHP a good replacing and competing technology.However,the LHP is a complex system, into which thermal and hydrodynamic mechanisms between the various LHP components are strongly coupled.As an ex-ample,temperature and pressure dynamic instabilities,such as under-and overshoot,are sometimes experimentally reported after changes in operational conditions(e.g.variations in heat load and sink temperature)[4,14–16].Under certain conditions, the LHP can even never really reach a true steady-state,but in-stead displays an oscillating behaviour[17–19].Such dynamic behaviours can induce various types of failure,like evaporator dry-out,degradation of performance,temperature oscillations, which are not suitable for the thermal control of electronics.Currently,LHP miniaturization is in the forefront of an ex-tensive research and development to provide cooling solutions to the high heat load/heatﬂux problem of advanced electronic packaging[20–28].The constrained space of such applications requires to design speciﬁc LHPs.Various models have been de-veloped for the LHP characterization[7,23,29–32].The steady state models are useful to size new-designed LHPs and to pre-dict LHP performance for variousﬁxed external conditions. All these studies contribute to the improvement of the under-standing of LHP operation and help to point out how various parameters may affect their behaviour.In the present paper,an exhaustive review of the parameters affecting the steady-state LHP operation is performed,based on the most recent pub-lished experimental and theoretical results.This review is hence to be regarded as an update extension of two previous review ar-unay et al./International Journal of Thermal Sciences46(2007)621–636623 NomenclatureA cross-sectional area........................m2 c p speciﬁc heat........................J kg−1K−1G thermal conductance....................W K−1H height......................................m k thermal conductivity...............W m−1K−1 l thickness...................................m L length......................................m L v latent heat of vaporization...............J kg−1 LHP loop heat pipe˙m massﬂow rate..........................kg s−1 M mass......................................kg Nu Nusselt numberNCG non-condensable gasP pressure...................................Pa Pe Peclet numberQ heat transfer rate............................W r radius of curvature..........................m R thermal resistance......................K W−1 R p pore radius.................................m T temperature.................................K u velocity................................m s−1 V volume....................................m3 Greek symbolsα,βvoid fraction θcontact angle...........................degree ρdensity................................kg m−3σsurface tension.........................N m−1 Subscriptsaxial axialc cold casecond condensercap capillarycc compensation chambere evaporator,evaporationeff effectiveg gravitygroove grooveh hot casein inlet of the compensation chamberl liquidmax maximumpw primary wicksat saturationsw secondary wickt totalv vapourw wickticles by Ku[33]and Maydanik[1]:the former focused on LHP operating characteristics while the latter mainly dealt with LHP designs and applications.2.LHP theory2.1.LHP descriptionThe operation of a LHP is based on thesame physical processes as those of conventional heat pipes.The LHP con-sists of a capillary pump(also called evaporator),a compensa-tion chamber(also called reservoir),a condenser,and vapour and liquid transport lines(Fig.1).Only the evaporator and the compensation chamber contain wicks;the rest of the loop can be made in smooth tubing.The compensation chamber is the largest component(by volume)of the loop and is often an integral part of the pump.It has two mains functions:(i)to accommodate excess liquid in the loop during normal opera-tion,and(ii)to supply the capillary pump wick with liquid at all times.To facilitate the latter function,a secondary wick isset-up between the pump wick and the reservoir.The wick in the evaporator,called“primary wick”,is made ofﬁne pores for purpose of developing a high capillary pressure to circulate theﬂuid around the loop,while the secondary wick is made of large pores for the purpose of managing theﬂuidﬂow between the compensation chamber and the evaporator.The secondary wick physically connects the evaporator to the reservoir in or-der to supply the primary wick with liquid,particularly whenFig.1.Geometry of a LHP.the reservoir is below the evaporator or in microgravity condi-tions.The heat exchanger,around the condenser line,can be of any type since it can transfer the waste heat efﬁciently to the sink.Both liquid and vapour lines are made of small-diameter tubing that can easily be arranged in tight spaces around the electronic devices.A portion of the liquid line(called bayonet)unay et al./International Journal of Thermal Sciences46(2007)621–636usuallyﬁrst exchanges heat with the reservoir,before it feeds the liquid returning to the capillary pump[34].2.2.LHP operating principlesThe operating principle of the LHP[1,33,35,36]is as fol-lows.Under steady state conditions,for a heat input Q e sup-plied to the evaporator,liquid is vaporized,and the menisci formed at the liquid/vapour interface in the evaporator wick develop capillary forces to pump the liquid from the compensa-tion chamber.Since the wick has aﬁnite thermal resistance,the vapour temperature and pressure in the evaporator zone(vapour grooves),which is in contact with the heated evaporator wall, become higher than the temperature and pressure in the com-pensation chamber.The wick in this case serves as a“thermal lock”.At the same time,hotter vapour cannot penetrate into the compensation chamber through the saturated wick owing to the capillary forces which hold the liquid in it(the interface will hold the pressure,preventing any backﬂow and at the same time providing uninterrupted liquidﬂow).Thus,another function of the wick is that of a“hydraulic lock”.The arising pressure dif-ference causes the displacement of the workingﬂuid around the loop.In this case,three interfaces may exist in the LHP simul-taneously:in the evaporator zone,in the condenser and in the compensation chamber.Except in the evaporator,these inter-faces may move depending on the heat load,and the excess of liquid is stored into the compensation chamber[1].A major part Q e,v of the heat input Q e is used for the liq-uid vaporization on the outer surface of the primary wick.The vapour generated in the evaporator travels along the vapour line to the heat exchanger where it rejects heat to a sink and turns back to liquid phase.The rest of the heat input,Q e,cc (called“heat leak”)is conducted across the wick and tends to increase the compensation chamber temperature.The amount of heat leak is proportional to the saturation temperature dif-ference between the evaporator and the compensation chamber T w. T w is a direct result of the pressure difference across the wick,induced by the vapour,condenser and liquid line pressure drops.The coupling between the pressure drop and the temper-ature drop across the evaporator wick is responsible for many of the peculiar behaviours found in LHP operation.Thus:Q e=Q e,v+Q e,cc(1) Q e,v=˙mL v(2) Q e,cc=G e,cc T w=G e,cc(T e−T cc)(3) where˙m is the massﬂow rate,and G e,cc is the thermal conduc-tance between the evaporator and the compensation chamber.G e,cc is usually difﬁcult to estimate,all the more since it may depend on the evaporator core state,ﬁlled with liquid or not. The effect of the liquid distribution between the compensation chamber and the evaporator core on the LHP performance is discussed in Section3.As described above,additional heat going to the compen-sation chamber tends to increase its temperature.At a speciﬁc heat input,an increase in the compensation chamber tempera-ture tends to reduce the two-phaseﬂow length in the condenser.A subcooled liquidﬂow region will appear before the condenser outlet.Then,the liquid subcooling will compensate a part of the heat leak in the compensation chamber:Q e,cc=˙mc p l(T cc−T in)(4) where c plis the liquid speciﬁc heat and T in is the liquid tem-perature at the compensation chamber inlet.At this state,the condenser is divided into three regions:the superheated vapour ﬂow,the two-phaseﬂow and the subcooled liquidﬂow.The LHP reaches a steady-state operation as the heat leak is totally compensated by the liquid subcooling.The LHP will adjust the saturation temperature until the energy balances for all the loop elements are satisﬁed.The feedback adjustment of the loop temperature is called“LHP auto-regulation”.2.3.Thermodynamic analysisA thermodynamic analysis of a capillary two-phase sys-tem can help for the understanding of thermal and hydraulic processes in the LHP operation.A P–T diagram of a workingﬂuid cycle is given in Fig.2 when the LHP operates at a capillary controlled mode(P v> P cc).Some details concerning this operating mode are given in Section3.5.The numbers in the diagram correspond to the physical locations shown in Fig.1.The vapour generated at the evaporator wick outlet(point1)is at a saturation state.It becomes superheated at the exit of the grooves(point2)due to heating and pressure losses.Assuming that the vapour line is perfectly insulated,the vapour temperature drop can be ne-glected.Since the pressure continues to drop along the way, the vapour becomes more and more superheated relatively to the local saturation pressure until it reaches the entrance of the condenser(point3).The vapour releases its sensible heat and begins to condense inside the condenser(point4).The vapour condensation takes place along the saturation line where both the pressure and the temperature decrease.At point5,the vapour condensation is complete,and the liquid starts tobeFig.2.P–T diagram for LHP steady-state operation(capillary controlled mode)(Chuang[32],Ku[33]).unay et al./International Journal of Thermal Sciences46(2007)621–636625subcooled inside the condenser until it exits at point6.The sub-cooled liquidﬂows in the liquid line,while its temperature may increase or decrease,depending on whether the liquid looses or gains heat from the ambient.As the liquid reaches the compen-sation chamber inlet(point7),the workingﬂuid is heated up to point8.The liquid subcooling T7–8adjusts itself so that the energy balance of the whole loop is satisﬁed.From the thermodynamic states shown in Fig.2,the follow-ing condition must be satisﬁed for a LHP:P v−P cc= P t− P w=(d P/d T)(T v−T cc)(5) where T v is the saturation temperature of the vapour inside the evaporator grooves(point1),T cc is the saturation temper-ature of theﬂuid in the compensation chamber,and d P/d T is the slope of the pressure-temperature saturation line at T cc (point8).This equation states that,for a given pressure differ-ence between the evaporator and the compensation chamber, a corresponding difference in the saturation temperatures must also exist between the two elements so as to generate exactly the same pressure difference[33].The evolution from point8to9corresponds to the liquid ﬂow through the wick into the evaporation zone.On this way, the liquid may be superheated,but boiling does not take place because it remains in such a state for a too short time.Point9 determines the state of the workingﬂuid in the vicinity of the evaporating menisci,and the pressure drop P1–9corresponds to the value of total pressure losses along the whole loop.It should be noted that,in Fig.2,the cycle is enlarged to improve its legibility.2.4.LHP operating limitsSimilarly to conventional heat pipes,LHPs are subjected to a number of heat transfer limitations.Due to the various designs of LHPs,these limitations have magnitudes and characteristics different from those of conventional heat pipes[32,36].2.4.1.Viscous limitThe viscous limitation occurs when the operating tempera-ture is extremely low and the applied heat load is small.It refers to when the viscous forces are larger than the pressure gradients in the heatﬂow.Under this condition,there is noﬂow or low ﬂow in the system and the heat transport capability is limited. This situation is usually observed in cryogenic applications or during start-up from a frozen state[32].2.4.2.Sonic limitThe sonic limit is the maximum allowable massﬂow rate or heat transfer that could affect the loop heat pipe operation. The choked vapourﬂow rate occurs when the vapour reaches the sonic speed.This could happen if the duct cross-sectional area decreases while the workingﬂuid isﬂowing in the pipe. This would cause the vapour velocity to increase up to sonic speed where theﬂow would start to choke.Chokedﬂow could occur in a pipe of uniform cross section if the massﬂow rate was increased gradually along the axial direction,or if theﬂuid was accelerated due to phase change in the wick pores[36].2.4.3.Entrainment limitIn LHPs,since the liquid and vapourﬂows do not interact the one with the other,this limit is less important than in con-ventional heat pipes.Nevertheless,some entrainment is likely to occur at the outer surface of the primary wick:in this region, the liquid may be entrained by the high vapour massﬂow rate in the channel[32,36].2.4.4.Capillary limitFor a proper loop operation,the primary wick in the evapora-tor must have a sufﬁcient capillary pumping head to overcome pressure losses in the loop components[33].The total pressure drop in the system is the sum of frictional pressure drops in the evaporator grooves,the vapour line,the condenser,the liq-uid line,and the evaporator wicks,plus any static pressure drop due to gravity:P t= P groove+ P v+ P cond+ P l+ P w+ P g(6) The capillary pressure rise that the wick can develop is given by:P cap=P v−P l=2σ/r(7) whereσis the surface tension of the workingﬂuid,r is the curvature radius of the meniscus in the wick,and P l is the liq-uid pressure under the meniscus at point9.As the heat load to the evaporator increases,so will the massﬂow rate and the total pressure drop in the system.The wick reaches its maxi-mum capillary pumping capability P cap,max as r=R p/cosθ, where R p is the pore radius of the wick andθis the contact angle between the liquid and the wick.Further increase in the heat load will lead to the vapour penetration into the wick and ﬁnally to the system deprime.Thus,under normal operation, the following condition must be satisﬁed all the time:P cap,max P t(8) The pore radius R p,usually given among the wick character-istics,corresponds to the mean pore radius of the wick.As a wick is usually a heterogeneous material,R p should correspond to the largest pore radius of the wick[36].Moreover,especially for cylindrical evaporators,the vaporized massﬂow rate may be nonuniform all around the wick outer surface.Then,the capil-lary limitation may appear in some speciﬁc locations,inducing a wick partial dry-out.Consequently,the local heat transfer co-efﬁcient at the vaporization area is reduced,but the LHP still operates.2.4.5.Boiling limitThe evaporator design of LHPs has the ability to tolerate the boiling limit better than heat pipes because heat is conducted from the evaporator body to the primary wick,so that the liq-uid evaporates at the outer surface of the wick.Boiling may still occur right below the heating surface when the heat load is ex-cessively high.However,the generated vapour bubbles can be vented out to the vapour channel easily[32].The temperature difference needed for nucleation is given by Dhir et al.[37]:T l−T sat=(2σ/R p−P NCG)T satρv L v(9)unay et al./International Journal of Thermal Sciences 46(2007)621–636According to Kaya and Goldak [38],who have developed a numerical modelling of heat and mass transfer in the cap-illary structure of a LHP,it is desirable to maintain a very good contact at the ﬁn-wick interface and to eliminate the non-condensable gases in order to increase the boiling limit.3.LHP parametric studyA parameter study on the LHP operation is difﬁcult as strongly coupled physical mechanisms are involved in LHPs.Each parameter effect has been deduced from theoretical analy-sis,experimental observations or numerical studies.We should keep in mind that in most of the studies,ammonia is the work-ing ﬂuid.The use of ﬂuids of lower pressure may amplify the sensitivity of the LHP operation to some parameters.3.1.Effect of ﬂuid chargeThe compensation chamber volume V cc must be able to accommodate at least the liquid volume swing (and density changes)between the hot case and the cold case of the loop operation [33].The ﬂuid inventory must satisfy the following relationships for the cold and the hot cases,respectively:M =ρl,cV l +V pw +V sw +V groove +V v +V cond+(1−β)V cc+ρv,c βV cc (10)M =ρl,h V l +V pw +V sw +(1−α)V cc+ρv,h [V groove +V v +V cond +αV cc ](11)where V l is the volume of the liquid line;V pw and V sw are the void volumes of the primary wick and secondary wick,respec-tively;V groove ,V v ,and V cond are the volumes of the evaporator grooves,the vapour line and the condenser,respectively.βand αcorrespond to the void fraction of the ﬂuid in the compensa-tion chamber at the cold and hot cases,respectively.βand αare selected at the designer’s discretion.Once these values are determined,the compensation chamber volume and the ﬂuid inventory can be calculated from the above equations.At any operating mode of the LHP,both liquid and vapour phases have to coexist in the compensation chamber.Then,it is meaningful to study the ﬂuid charge effect on the LHP performance as long as the compensation chamber is ﬁlled with a two-phase ﬂuid.From the thermodynamic analysis,the ﬂuid charge has no effect on the steady-state LHP performance.However,from the thermal analysis,whether or not the evaporator core contains liquid and/or vapour bubbles may affect the radial heat leak,which has a signiﬁcant impact on the loop operation.Indeed,the evaporator core may contain liquid or vapour depending on the ﬂuid charge or the LHP position.The presence of vapour bubbles in the evaporator core shortens the heat ﬂow path and signiﬁcantly increases the heat leak.The evaporator core may act as a heat pipe,transferring efﬁciently heat from the wick internal surface to the compensation chamber.Ku et al.[14]have presented an experimental study of a loop heat pipe at low power operation,using ammonia as the work-ing ﬂuid.The ﬂuid inventory and the relative tilt between the evaporator and the compensation chamber were varied so astoFig.3.Q max and R th vs.working ﬂuid ﬁll charge ratio (methanol—1.0µm LHP for T in =20◦C)(Boo et al.[40]).create various void fractions in the evaporator core.The test results indicate that the vapour void fraction inside the evapo-rator core is the most important factor in controlling the loop operation at low heat loads.Consequently,a wick with a low thermal conductivity is highly desirable because it will reduce the heat leak,and hence mitigate the effect of the void fraction.The effect of the heat leak on the LHP operating temperature is presented in Section 3.6.Lee et al.[39]have investigated the LHP optimum ﬁll charge ratio and the heat ﬂux conditions,based on experimental mea-surements at horizontal position.For this speciﬁc LHP,the compensation chamber is located above the wick.Thus,the modiﬁcation of the ﬁlling ratio tends to modify the liquid height above the wick.Two kinds of sintered metal wick (stainless steel and brass)have been tested and distilled water was used as the working ﬂuid.The ﬁll charge ratio ranged from 40vol%to 60vol%and the imposed heat ﬂux was varied from 1.5W cm −2to 5.9W cm −2.Whatever the used sintered metal wick and the imposed heat ﬂux,the best heat transfer performance was mea-sured for the 51.3vol%ﬁlling ratio.For a similar LHP conﬁguration as Lee et al.[39],but using methanol as the working ﬂuid and a polypropylene (PP)porous wick,Boo and Chung [40]did not observe any signiﬁcant effect of the ﬁll charge ratio on the LHP thermal resistance (Fig.3).Nevertheless,the experimental results indicate a maximum heat load for an optimum value of the ﬁll charge ratio of 0.4–0.5.The maximum heat load was characterized by a maximum heater surface temperature of 90◦C,value beyond which the PP wick may be permanently deformed.Contrarily to the LHP steady-state operation,the LHP start-up is strongly inﬂuenced by the ﬂuid charge,and particularly by the ﬂuid distribution in the LHP before starting.Even with the same boundary conditions imposed on a same LHP,drastic ran-dom discrepancies of the wall superheat prior to the LHP start-up were experimentally observed [4].The presence of vapour bubbles/slugs in the evaporator grooves and/or in the evaporator core may modify the heat ﬂux ratio going to the compensa-tion chamber,which affects the temperature evolution in the。

heatpipe

Heat pipes for electronics coolingapplicationsScott D. Garner, PE., Thermacore IncFigure 1: Heat pipe operationIntroductionAll electronic components, from microprocessors to high end power converters, generate heat and rejection of this heat is necessary for their optimum and reliable operation. As electronic design allows higher throughput in smaller packages, dissipating the heat load becomes a critical design factor. Many of today's electronic devices require cooling beyond the capability of standard metallic heat sinks. The heat pipe is meeting this need and is rapidly becoming a main stream thermal management tool.Heat pipes have been commercially available since the mid 1960's. Only in the past few years, however, has the electronics industry embraced heat pipes as reliable, cost-effective solutions for high end cooling applications. The purpose of this article is to explain basic heat pipe operation, review key heat pipe design issues, and to discuss current heat pipe electronic cooling applications.Heat Pipe OperationA heat pipe is essentially a passive heat transfer device with an extremely high effective thermal conductivity. The two-phase heat transfer mechanism results in heat transfer capabilities from one hundred to several thousand times that of an equivalent piece of copper.As shown in Figure 1, the heat pipe in its simplest configuration is a closed, evacuated cylindrical vessel with the internal walls lined with a capillary structure or wick that is saturated with a working fluid. Since the heat pipe is evacuated and then charged with the working fluid prior to being sealed, the internal pressure is set by the vapor pressure of the fluid.As heat is input at the evaporator, fluid is vaporized, creating a pressure gradient in the pipe. This pressure gradient forces the vapor to flow along the pipe to a cooler section where it condenses giving up its latent heat of vaporization. The working fluid is then returned to the evaporator by the capillary forces developed in the wick structure.Heat pipes can be designed to operate over a very broad range of temperatures from cryogenic (< -243°C) applications utilizing titanium alloy/nitrogen heat pipes, to high temperature applications (>2000°C) using tungsten/silver heat pipes. In electronic cooling applications where it is desirable to maintain junction temperatures below 125-150°C, copper/water heat pipes are typically used. Copper/methanol heat pipes are usedif the application requires heat pipe operation below 0°C.Heat Pipe DesignThere are many factors to consider when designing a heat pipe: compatibility of materials, operating temperature range, diameter, power limitations, thermal resistances, and operating orientation. However, the design issues are reduced to two major considerations by limiting the selection to copper/water heat pipes for cooling electronics. These considerations are the amount of power the heat pipe is capable of carrying and its effective thermal resistance. These two major heat pipe design criteria are discussed below.Limits To Heat TransportThe most important heat pipe design consideration is the amount of power the heat pipeis capable of transferring. Heat pipes can be designed to carry a few watts or several kilowatts, depending on the application. Heat pipes can transfer much higher powers for a given temperature gradient than even the best metallic conductors. If driven beyond its capacity, however, the effective thermal conductivity of the heat pipe will be significantly reduced. Therefore, it is important to assure that the heat pipe is designed to safely transport the required heat load.The maximum heat transport capability of the heat pipe is governed by several limiting factors which must be addressed when designing a heat pipe. There are five primary heat pipe heat transport limitations. These heat transport limits, which are a function of the heat pipe operating temperature, include: viscous, sonic, capillary pumping, entrainment or flooding, and boiling. Figures 2 and 3 show graphs of the axial heat transport limits asa function of operating temperature for typical powder metal and screen wicked heat pipes. Each heat transport limitation is summarized in Table 1.Heat Transport Limit Description Cause Potential SolutionViscousViscous forces preventvapor flow in the heat pipeHeat pipe operating belowrecommended operatingtemperatureIncrease heat pipeoperating temperature orfind alternative workingfluidSonicVapor flow reaches sonicvelocity when exiting heatpipe evaporator resulting ina constant heat pipetransport power and largetemperature gradientsPower/temperaturecombination, too muchpower at low operatingtemperatureThis is typically only aproblem at start-up. Theheat pipe will carry a setpower and the large ^Twill self correct as theheat pipe warms upEntrainment/Flooding High velocity vapor flowprevents condensate fromreturning to evaporatorHeat pipe operating abovedesigned power input or attoo low an operatingtemperatureIncrease vapor spacediameter or operatingtemperatureCapillary Sum of gravitational, liquidand vapor flow pressuredrops exceed the capillarypumping head of the heatpipe wick structureHeat pipe input powerexceeds the design heattransport capacity of theheat pipeModify heat pipe wickstructure design or reducepower inputBoilingFilm boiling in heat pipeevaporator typically initiatesat 5-10 W/cm2 for screenwicks and 20-30 W/cm2 forpowder metal wicksHigh radial heat flux causesfilm boiling resulting inheat pipe dryout and largethermal resistancesUse a wick with a higherheat flux capacity orspread out the heat load Table 1: Heat pipe heat transport limitationsFigure 2: Predicted heat pipe limitationsAs shown in Figures 2 and 3, the capillary limit is usually the limiting factor in a heat pipe design.Figure 3: Predicted heat pipe limitsThe capillary limit is set by the pumping capacity of the wick structure. As shown in Figure 4, the capillary limit is a strong function of the operating orientation and the type of wick structure.Figure 4: Capillary limits vs. operating angleThe two most important properties of a wick are the pore radius and the permeability. The pore radius determines the pumping pressure the wick can develop. The permeability determines the frictional losses of the fluid as it flows through the wick. There are several types of wick structures available including: grooves, screen, cables/fibers, and sintered powder metal. Figure 5 shows several heat pipe wick structures.It is important to select the proper wick structure for your application. The above list is in order of decreasing permeability and decreasing pore radius.Grooved wicks have a large pore radius and a high permeability, as a result the pressure losses are low but the pumping head is also low. Grooved wicks can transfer high heat loads in a horizontal or gravity aided position, but cannot transfer large loads against gravity. The powder metal wicks on the opposite end of the list have small pore radii and relatively low permeability. Powder metal wicks are limited by pressure drops in the horizontal position but can transfer large loads against gravity.Effective Heat Pipe Thermal ResistanceThe other primary heat pipe design consideration is the effective heat pipe thermal resistance or overall heat pipe T at a given design power. As the heat pipe is a two-phase heat transfer device, a constant effective thermal resistance value cannot be assigned. The effective thermal resistance is not constant but a function of a large number of variables, such as heat pipe geometry, evaporator length, condenser length, wick structure, and working fluid.Figure 5: Wick structuresThe total thermal resistance of a heat pipe is the sum of the resistances due to conduction through the wall, conduction through the wick, evaporation or boiling, axial vapor flow, condensation, and conduction losses back through the condenser section wick and wall.Figure 6 shows a power versus T curve for a typical copper/water heat pipe.Figure 6: Predicted heat pipe Delta-TTThe detailed thermal analysis of heat pipes is rather complex. There are, however, a few rules of thumb that can be used for first pass design considerations. A rough guide for a copper/water heat pipe with a powder metal wick structure is to use 0.2°C/W/cm2 for thermal resistance at the evaporator and condenser, and 0.02°C/W/cm2 for axial resistance.The evaporator and condenser resistances are based on the outer surface area of the heat pipe. The axial resistance is based on the cross-sectional area of the vapor space. This design guide is only useful for powers at or below the design power for the given heat pipe.For example, to calculate the effective thermal resistance for a 1.27 cm diametercopper/water heat pipe 30.5 cm long with a 1 cm diameter vapor space, the following assumptions are made. Assume the heat pipe is dissipating 75 watts with a 5 cm evaporator and a 5 cm condenser length. The evaporator heat flux (q) equals the power divided by the heat input area (q = Q/A evap; q = 3.8 W/cm2). The axial heat flux equals the power divided by the cross sectional area of the vapor space (q=Q/A vapor; q = 95.5W/cm2).The temperature gradient equals the heat flux times the thermal resistance.T = q evap * R evap + q axial * R axial + q cond * R condT = 3.8 W/cm2 * 0.2°C/W/cm2 + 95.5 W/cm2 * 0.02°C/W/cm2+ 3.8 W/cm2 * 0.2°C/W/cm2T = 3.4°CIt is important to note that the equations given above for thermal performance are only rule of thumb guidelines. These guidelines should only be used to help determine if heat pipes will meet your cooling requirements, not as final design criteria. More detailed information on power limitations and predicted heat pipe thermal resistances are given in the heat pipe design books listed in the reference section.Heat Pipe Electronic Cooling Applications:Perhaps the best way to demonstrate the heat pipes application to electronics cooling is to present a few of the more common examples. Currently, one of the highest volume applications for heat pipes is cooling the Pentium processors in notebook computers. Due to the limited space and power available in notebook computers, heat pipes are ideally suited for cooling the high power chips.Fan assisted heat sinks require electrical power and reduce battery life. Standard metallic heat sinks capable of dissipating the heat load are too large to be incorporated into the notebook package. Heat pipes, on the other hand, offer a high efficiency, passive, compact heat transfer solution. Three or four millimeter diameter heat pipes can effectively remove the high flux heat from the processor. The heat pipe spreads the heat load over a relatively large area heat sink, where the heat flux is so low that it can be effectively dissipated through the notebook case to ambient air. The heat sink can be the existing components of the notebook, from Electro-Magnetic Interference (EMI) shielding under the key pad to metal structural components. Various configurations of notebook heat pipe heat sinks are shown in Figure 7.Figure 7: Typical notebook heat pipe heat sinkTypical thermal resistances for these applications at six to eight watt heat loads are 4 - 6°C/watt. High power mainframe, mini-mainframe, server and workstation chips may also employ heat pipe heat sinks. High end chips dissipating up to 100 watts are outside the capabilities of conventional heat sinks. Heat pipes are used to transfer heat from the chip to a fin stack large enough to convect the heat to the supplied air stream. The heatpipe isothermalizes the fins eliminating the large conductive losses associated with standard sinks. The heat pipe heat sinks, shown in Figure 8, dissipate loads in the 75 to 100 watt range with resistances from 0.2 to 0.4°C/watt, depending on the available air flow.Figure 8: High end CPU heat pipe heat sinkIn addition, other high power electronics including Silicon Controlled Rectifiers (SCR's), Insulated Gate Bipolar Transistors (IGBT's) and Thyristors, often utilize heat pipe heat sinks. Heat pipe heat sinks similar to the one shown in Figure 9, are capable of cooling several devices with total heat loads up to 5 kW. These heat sinks are also available in an electrically isolated versions where the fin stack can be at ground potential with the evaporator operating at the device potentials of up to 10 kV. Typical thermal resistances for the high power heat sinks range from 0.05 to 0.1°C/watt. Again, the resistance is predominately controlled by the available fin volume and air flow.Figure 9: High power IGBT heat pipe heat sink。

MORNSUN URF1D_HB-150WSeries 高性能电源 DC DC 转换器说明书

150W,wide input voltage,isolated &regulated single output DC-DC converterFEATURES●Wide input voltage range:50-160V ●High efficiency up to 91%●No-load power consumption as low as 3mA ●Isolation voltage 3000VDC●Operating temperature range:-40℃to +100℃●Input under-voltage protection,output over-voltage,over-current,short circuit,over-temperature protection ●International standard:1/2brick●Meets requirementsof railway standardEN50155Patent Protection RoHSURF1D_HB-150W series is a high performance product designed for the field of railway applications.Output power up to 150W,no min load requirement,wide input voltage 50-160VDC,which allows the base plate operating temperature up to 100℃.Further product feathers include input under-voltage protection,output over-voltage protection,short circuit protection,over current protection,over temperature protection,remote control and compensated,output voltage regulation functions.Meets the EN50155railway standard.Widely used in the on-board electronic system and associated equipment.Selection GuidePart No.①Input Voltage (VDC)OutputEfficiency (%,Min./Typ)@Full LoadMax.CapacitiveLoad(µF)Nominal (Range)Max.②Output Voltage(VDC)Output Current (mA)(Max./Min.)URF1D12HB-150W 110(66-160)1701212500/087/8910000(50-66)10000/0URF1D15HB-150W (66-160)1510000/087/896800(50-66)8000/0URF1D24HB-150W(66-160)246250/089/914400(50-66)5000/0Note:①Series with suffix “H”are heat sink mounting;If the application has a higher requirement for heat dissipation,we recommend modules with heat sink;②Absolute maximum rating without damage on the converter,but it isn't recommended;Input SpecificationsItemOperating Conditions Min.Typ.Max.Unit Input Current (full load /no-load)Nominal input --1532/31567/10mAReflected Ripple CurrentNominal input--80--Input impulse Voltage (1sec.max.)-0.7--180VDC Starting Voltage--4750Under-voltage Shutdown Voltage 354350Start-up Time --25--mSInput FilterPi filterCtrl*Module switch onCtrl psuspended or connected to TTL high level (3.5-12VDC)Module switch offCtrl connected to -Vin or low level (0-1.2VDC)Input current when switched off--25mAHot PlugUnavailableNote:*the voltage of Ctrl pin is relative to input pin -Vin.Output SpecificationsItemOperating Conditions Min.Typ.Max.Unit Output Voltage Accuracy Nominal input,10%-100%load--±1±3%Line RegulationFull load,the input voltage is from low to high----±0.3Load Regulation Nominal input,10%-100%load----±0.5Transient Recovery Time 25%load step change --300500µs Transient Response Deviation 15V ，24V output --±3±5%Vo 12V output--±4±8Temperature Coefficient Full load----±0.03%/℃Ripple &Noise *20MHz bandwidth (with 10%-100%load)--60150mVp-pOutput voltage Regulated range(Trim)95--110%Vo Output voltage remote compensation(Sense)----105Over-voltage Protection Input voltage range 110--140%Vo Over-current Protection 110130180%Io Short circuit ProtectionNominal input Hiccup,continuous,self-recoveryNote:*The measuring method of ripple and noise,please refer to Fig.2.General SpecificationsItem Operating ConditionsMin.Typ.Max.UnitIsolation VoltageInput-outputInput-output,with the test time of 1minuteand the leak current less than 1mA 3000----VDC Input-aluminum plate 1500----Output-aluminum plate1000----Isolation Resistance Input-output,insulation voltage 500VDC 1000----M ΩIsolation Capacitance Input-output,100KHz/0.1V--2500--pF Operating Temperature See Temperature Derating Curve Fig.1-40--100℃Base-Plate Temperature Within the operating temperature curve -40--100Storage Temperature -55--125Over-temperature Protection Base-Plate Temperature100--120Pin Welding Resistance Temperature Welding spot is 1.5mm away from the casing,10seconds ----300Storage HumidityNon-condensing 5--95%RH Thermal ResistanceURF1D12HB-150W URF1D15HB-150W URF1D24HB-150WNatural convection7.8----℃/W 200LFM convection 4.44----400LFM convection 3.39----1000LFM convection 2.52----URF1D12HB-150WH URF1D15HB-150WH URF1D24HB-150WHNatural convection 3.7----200LFM convection 2.2----400LFM convection 1.76----1000LFM convection 1.28----Switching Frequency PWM mode--160--KHz MTBFMIL-HDBK-217F@(Plate Tb=70℃,GB)500----K hours Shock and Vibration TestIEC61373car 1classBPhysical SpecificationsCasing Material Aluminum plate +plastic case Black flame-retardant and heat-resistant plastic (UL94-V0)HeatsinkAluminum Alloy WeightURF1D12HB-150W 、URF1D15HB-150W 、URF1D24HB-150W 70g (Typ.)URF1D12HB-150WH 、URF1D15HB-150WH 、URF1D24HB-150WH120g (Typ.)Cooling methodNatural convection or Forced convectionEMC SpecificationsEMICE CISPR32/EN55032Class B (see Fig.4)RECISPR32/EN55032Class B (see Fig.4)EMSESDIEC/EN61000-4-2Contact ±6KV,Air±8KV perf.Criteria B GB/T17626.2RS IEC/EN61000-4-310V/m perf.Criteria A GB/T17626.3EMSCSIEC/EN61000-4-610Vr.m.sperf.CriteriaA GB/T17626.6EFT IEC/EN61000-4-4±2KV(5KHz/100KHz)(see Fig.4for recommended circuit)perf.CriteriaB GB/T17626.4SurgeIEC/EN61000-4-5±2KV(1.2μs/50μs 2Ω)(see Fig.4for recommended circuit)perf.Criteria BGB/T17626.5Efficiency CurvesTemperature Derating CurveFig.1Sense of application and precautions1.When Remote Sense is not used0V+Vo sens e+Trim sens e-+C The lead as s hort as poss ibleLoadNotes ：1.When remote sense is not used,make sure +Vo and Sense +are shorted,and that 0V and Sense-are shorted as well;2.Keep the patterns between +Vo and Sense +and 0V and Sense-as short as possible.Avoid a looping pattern.If noise enters the loop,the operation of the power module will become unstable.2.When Remote Sense is used0V+Vo sens e+Trim sens e-Load+C Notes:ing remote sense with long wires may cause output voltage to become unstable.Consult us if long sensing wiring is necessary.2.Sense patterns or wires should be as short as possible.If wires are used,use either twisted-pair or shielded wires.3.Please Use wide PCB trace or a thick wires between the power supply module and the load,the line voltage drop should be kept less than 0.3V.Make sure the power supply module's output voltage remains within the specified range.4.The impedance of wires may cause the output the voltage oscillation or have a greater ripple,please do adequate assessments before using.Design Reference1.Ripple &noiseAll the URF1D_QB-100W series have been tested according to the following recommended test circuit before leaving the factory (see Fig.2)，Ripple &noise tested according to Fig.30V+Vo 25.4m m51m mC 2C 12.54m msense +Trim sense --VinCtrl+V inC 0DC Inp ut100u F 1u F10u Fnectllogr aph Probe z ba ndw idth )LoadCa seFig.22.Typical applicationIf not using our Mornsun’s EMC recommended circuit,please ensure an 100μF electrolytic capacitors in parallel with the input,which used to suppress the surge voltage come from the input terminal.If it is required to further reduce input and output ripple,properly increase the input &output of additional capacitors Cin and Cout or select capacitors of low equivalent impedance provided that the capacitance is no larger than the max.capacitive load of the product.DC DC0VCinCoutCapacitiveParameterOutput VoltageCout(µF)Cin(µF)12V 、15V 、24V2201003.EMC solution-module recommended circuit+Vin-Vin+Vo0V DC/DCLCM1+VinC3C4C5LDM1C0C2C 1Y CY2C6C7MOV1FUSEC1C8Fig.4Element modelRecommended valueFUSE Choose according to actual input currentMOV1S20K130(Varistor)C0220uF/200V (electrolytic capacitor)C1/C2100uF/200V (electrolytic capacitor)C3/C4/C5/C6/C72.2uF/250VC8220uF/50V(electrolytic capacitor)CY12200pF/400V AC (Y Safety capacitor)CY23300pF/400V AC (Y Safety capacitor)LDM110uH (Shielded inductor)LCM11.0mH,recommended to use MORNSUN’s FL2D-30-1024.Thermal designThe maximum operating temperature of base-plate TB is 100℃,as long as the user's thermal system keeps TB <100℃,the converter can deliver its full rated power.A power derating curve can be calculated for any heatsink that is attached to the base-plate of the converter.It is only necessary to determine the thermal resistance,Rth(B-A),of the chosen heatsink between the base-plate and the ambient air for a given airflow rate.This information is usually available from the heatsink vendor.The following formula can the be used to determine the maximum power the converter can dissipate for a given thermal condition if its base-plate is to be no higher than 100ºC.）（℃A -B Amax th 100R T P diss -=(T A is ambient temperature)The maximum load operating power of power supply module at a certain ambient temperature can be calculated by the power dissipation,Formula is as follows:)11(max max -=ηdissP Po (ηis converter efficiency)Therefore,customers can according to the actual application to choose the right heatsink.5.Application of Trim and calculation of Trim resistanceR 2R 1R 3V ref R TR 2R 1R 3V ref R T+VotTrim upTrim downApplied circuits of Trim (Part in broken line is the interior of models)Calculation formula of Trim resistance:up: a=VrefVo’-Vref R 1R =T aR 2R -a 2-R 3down: a=VrefVo’-VrefR 2R =T aR 1R -a1-R 3Note ：Value for R1,R2,R3,and V ref refer to the above table 1.R T :Resistance of Trim.a:User-defined parameter,no actual meanings.Vo’:The trim up/down voltage.table 1VoParameter12(VDC)15(VDC)24(VDC)R1(K Ω)1114.4924.87R2(K Ω) 2.87 2.87 2.87R3(K Ω)17.82020Vref(V)2.52.52.56.It is not allowed to connect modules output in parallel to enlarge the power7.For more information about Mornsun EMC Filter products,please visit todownload the Selection Guide of EMC FilterDimensions and Recommended Layout(Without heatsink) Dimensions(With heatsink)Note1.Packing information please refer to Product Packing Information which can be downloaded from .Packingbag number:58200069(without heatsink)、58200061(with heatsink);2.The max capacitive load should be tested within the input voltage range and under full load conditions;3.Recommends that customers plus silicone film or thermal grease between the module and the heatsink,In order to ensure good heatdissipation;4.Unless otherwise specified,parameters in this datasheet were measured under the conditions of Ta=25℃,humidity<75%RH with nominalinput voltage and rated output load;5.when used in lower than10%load,the ripple&noise index of the product is3%Vo;6.All index testing methods in this datasheet are based on our Company’s corporate standards;7.The performance parameters of the product models listed in this manual are as above,but some parameters of non-standard modelproducts may exceed the requirements mentioned above.Please contact our technicians directly for specific information;8.We can provide product customization service,please contact our technicians directly for specific information;9.Products are related to laws and regulations:see"Features"and"EMC";10.Our products shall be classified according to ISO14001and related environmental laws and regulations,and shall be handled byqualified units.Mornsun Guangzhou Science&Technology Co.,Ltd.Address:No.5,Kehui St.1,Kehui Development Center,Science Ave.,Guangzhou Science City,Luogang District,Guangzhou,P.R.China Tel:86-20-38601850-8801Fax:86-20-38601272E-mail:***************。

缺氧高压制氧模块用导热水管

缺氧高压制氧模块用导热水管英文回答：Hyperbaric Oxygenation Chamber with Hot Water Heating Pipe.To create a hyperbaric oxygenation chamber with a hot water heating pipe, the following materials and tools will be needed:A large, airtight chamber (such as a steel drum or a fiberglass tank)。

A high-pressure oxygen source (such as a medical-grade oxygen cylinder)。

A hot water heating pipe (such as a copper orstainless steel pipe)。

A submersible water pump.A temperature gauge.A pressure gauge.A safety valve.A timer.Various fittings and connectors.The first step is to prepare the chamber. Ensure that the chamber is airtight by sealing any leaks with silicone or epoxy. The chamber should be large enough to accommodate the person or animal undergoing hyperbaric oxygenation, as well as the heating pipe and other equipment.Next, install the hot water heating pipe inside the chamber. The pipe should be positioned so that it will heat the air inside the chamber evenly. The pipe can be secured using brackets or clamps.Connect the heating pipe to the submersible water pump. The pump will circulate hot water through the pipe, heating the air inside the chamber. The pump should be sized appropriately for the volume of the chamber and the desired temperature.Install the temperature gauge and pressure gauge inside the chamber. The temperature gauge will allow you to monitor the temperature of the air inside the chamber. The pressure gauge will allow you to monitor the pressureinside the chamber.Connect the high-pressure oxygen source to the chamber. The oxygen source should be regulated to provide a constant flow of oxygen at the desired pressure. The pressure should be set according to the prescribed treatment protocol.Install a safety valve on the chamber. The safety valve will release excess pressure in the event that the pressure inside the chamber becomes too high.Set the timer to the desired treatment time. Thetreatment time will vary depending on the condition being treated.Once the chamber is set up, you can begin the hyperbaric oxygenation treatment. To do this, simply close the chamber door and start the timer. The submersible water pump will begin circulating hot water through the heating pipe, heating the air inside the chamber. The oxygen source will begin supplying oxygen to the chamber, increasing the pressure inside the chamber.The patient will remain in the chamber for the prescribed treatment time. During this time, they will breathe the high-pressure oxygen. The oxygen will dissolve into their bloodstream, increasing the oxygen levels in their tissues.After the treatment time is complete, the timer will sound an alarm. Open the chamber door and allow the patient to exit. The heating pipe will automatically shut off, and the pressure inside the chamber will gradually decrease.Hyperbaric oxygenation therapy can be an effective treatment for a variety of conditions, including decompression sickness, carbon monoxide poisoning, and severe infections. It can also be used to improve wound healing and reduce inflammation.中文回答：高压氧舱伴热水管。

射流微通道耦合高效散热器传热实验研究

第 21 卷第 11 期2023 年 11 月Vol.21，No.11Nov.，2023太赫兹科学与电子信息学报Journal of Terahertz Science and Electronic Information Technology射流微通道耦合高效散热器传热实验研究潘瑶，刘欣，巩萌萌(北京宇航系统工程研究所，北京100076)摘要：针对光导开关高重复频率运行时产生丝电流加热，使光导开关温度迅速超过材料最高允许使用温度，造成开关失效或损伤的难题，本文结合微通道散热技术和射流冷却技术的优点，设计了射流微通道耦合高效散热器。

通过实验测试，对不同运行工况下射流微通道耦合高效散热器的传热特性进行了研究，并与美国进口的蜂窝型微通道散热器进行散热性能对比。

实验结果表明：体积流量为3 L/min的情况下，射流微通道耦合高效散热器的换热系数超过35 000 W/(K·m2)，散热量高达1 000 W，相比蜂窝型微通道散热器散热量提升了45%。

在测试流量下，随着体积流量的增加，射流微通道耦合高效散热器的平均换热系数接近线性增加，而蜂窝型微通道散热器的平均换热系数在大流量下却增加缓慢。

此外，采用射流微通道耦合高效散热器冷却的热源面温度均匀性明显优于采用蜂窝型微通道散热器冷却的热源面温度均匀性，采用射流微通道耦合高效散热器的热源面温度波动能降低58%，更有利于降低光导开关热应力。

关键词：射流阵列；微通道；实验研究；光导开关中图分类号：TN015 文献标志码：A doi：10.11805/TKYDA2021318Experimental research on heat transfer characteristics of micro-channel/jet impingement heat sinkPAN Yao，LIU Xin，GONG Mengmeng(Beijing Institute of Astronautics System Engineering，Beijing 100076，China)AbstractAbstract：：During the period that the Photoconductive Semiconductor Switches(PCSS) is operating ata high repetition frequency, it generates filament current heating, then the temperature of the PCSSquickly exceeds the maximum operating temperature, causing the PCSS to fail or damage. Combining theadvantages of microchannel heat sink and jet cooling technology, a high-efficiency micro-channel/jetimpingement heat sink is designed. Through experimental tests, the heat transfer characteristics of themicro-channel/jet impingement heat sink under different operating conditions are studied, and the heatdissipation performance is compared with that of the honeycomb micro-channel heat sink imported fromthe United States. The experimental results show that when the volume flow rate is 3 L/min, the heattransfer coefficient of the micro-channel/jet impingement heat sink exceeds 35 000 W/(K·m2), and the heatdissipation is as high as 1 000 W, which is higher than that of the honeycomb microchannel heat sink by45%. Under the test flow rate, with the increase of the volume flow rate, the average heat transfercoefficient of the micro-channel/jet impingement heat sink approaches a linear increase. The averageheat transfer coefficient of the honeycomb micro-channel radiator increases slowly at large flow rates. Inaddition, compared with the method that cooled by the honeycomb microchannel heat sink, the uniformityof the heat source temperature cooled by the micro-channel/jet impingement heat sink is significantlybetter, and it can reduce the temperature fluctuation of the heat source surface by 58%,which is moreconducive to reduce the thermal stress of the PCSS.KeywordsKeywords：：jet array;micro-channel;experimental research;Photoconductive Semiconductor Switches 脉冲功率技术在高功率微波、强激光、生物医疗、污水处理等技术领域都有巨大应用潜力。

1250和1650A, 1395 DC 驱动器中的电机热栅集装置替换指南说明书

Armature Heatsink AssemblyReplacement(for 1250 and 1650A, 1395 DC Drives)Contents This document shows how to remove and replace a heatsink assemblyin a 1250 or 1650A, 1395 DC drive.What This Kit Contains Using the table below, verify that you have received the appropriateitems in your kit:For this part:You should receive this quantity:heatsink assembly1Other Items Needed Before you begin, be sure you also have the following:•Tools needed for:•Removing, fastening, and torquing bolts (ratchet withextension and a 9/16” socket, torque wrench for 25 lb-ft)•Testing for voltage (multimeter)•Documentation:•Your drive system schematics•Publication 1395-5.40, Bulletin 1395 Digital DC Drive–User Manual•Publication 2361-5.01, Bulletin 1395 Digital DC Drive inBulletin 2361 Motor Control Center for Drive Systems–User Manual2Armature Heatsink Assembly Replacement (for 1250 and 1650A, 1395 DC Drives)Publication 2361-5.17 - May 1998Safety PrecautionsThe following general precautions apply when working on drives:Special InstructionsImportant: You will need to reuse parts that are removed from the drive. Place parts, in the order removed, on a clean surface.Important: Some washers, such as clamp and Belleville washers, have only one correct orientation.!ATTENTION:Only those familiar with the drive system, the products used in the system, and the associated machinery should plan or implement the installation, startup, and future maintenance of the system. Failure to comply can result in personal injury and/or equipment damage.ATTENTION:Verify that all sources of AC and DC power are deenergized and locked out or tagged out in accordance with the requirements of ANSI/NFPA 70E, Part II.ATTENTION:The system may contain stored energy devices. To avoid the hazard of electrical shock, verify that all voltage on capacitors has been discharged before attempting to service, repair, or remove a drive system or its components. You should only attempt the procedures in this manual if you are qualified to do so and are familiar with solid-state control equipment and the safety procedures in publication NFPA 70E.ATTENTION:When servicing any unit, do not drop any nuts, bolts, washers, etc. inside the unit, as they may cause a short circuit on power up.ATTENTION:This drive system contains ESD (Electrostatic Discharge) sensitive parts and assemblies. Static control precautions are required when installing, testing, or repairing this assembly. Component damage can result if ESD control procedures are not followed. If you are not familiar with static control procedures, refer to Rockwell Automation publication 8000-4.5.2, Guarding Against Electrostatic Damage or any other applicable ESD protection handbook.Armature Heatsink Assembly Replacement (for 1250 and 1650A, 1395 DC Drives)3 Preliminary Steps Before replacing the heatsink assembly, shut off the drive power, waitfive minutes for the voltage to discharge, open the bridge bay door,and remove all Lexan™ guards shielding the heatsink assemblies. Notes on the Heatsink Assembly While this document covers the removal and installation of all 1250and 1650A drive heatsink assemblies, please note that the assembliescan be slightly different:•Lower assemblies (on the negative leg) do not have thermoswitchconnections and are built in an upside-down fashion from theupper assemblies.•Non-regenerative assemblies only have the lower AC heatsink,one armature-pulse transformer board, and one SCR installed.•Regenerative assemblies will have two AC heatsinks, twoarmature-pulse transformer boards, and two SCRs installed.Publication 2361-5.17 - May 19984Armature Heatsink Assembly Replacement (for 1250 and 1650A, 1395 DC Drives)Publication 2361-5.17 - May 1998Armature Heatsink Assembly Replacement (for 1250 and 1650A, 1395 DC Drives)5Publication 2361-5.17 - May 1998Removing the Assembly ing a voltmeter, test the voltage across the three phases, thenacross the heatsink assembly components.2.Unplug the thermoswitch connector (upper assemblies only).Note: Unplug thermoswitch connectors for any other assembliesif they are in the way.3.Unplug the gate lead connector from J1 on each armature-pulsetransformer board.Note: Unplug gate lead connectors for any other assemblies ifthey are in the way.4.Remove the two fuses from the front of the assembly.5.Remove the mounting bolts from the top and bottom of theassembly.6.Lift the heatsink assembly out of the drive.!ATTENTION:If there is any voltage present, removethe source of the voltage and check for voltages again before proceeding to the next step.!ATTENTION:Heatsink assemblies weigh 60-75 lbseach. Take the necessary precautions (following yourcompany’s material handling procedures) before lifting to avoid injury and equipment damage.6Armature Heatsink Assembly Replacement (for 1250 and 1650A, 1395 DC Drives)Replacing the Heatsink Assembly 1.Place the new assembly into the drive (with the snubbers to theright), and rest the lower bracket (or busbar) on the mounting peg.2.Mount the assembly, securing the three mounting bolts to the topand bottom of the assembly. Torque the Glastic™ surface to 25lb-ft and the busbar mounting surface to 25 lb-ft.3.Mount the two fuses with the label text upright, and the blackindicators away from each other. Torque the fuse bolts to25 lb-ft.4.Connect the gate lead connector to J1 on each armature-pulsetransformer board. Ensure that the connectors for all six assem-blies in the drive are secure.Note: Match the board names (i.e. A14R) with the wire labels(i.e. A14R-J1) to verify proper connections.5.Connect the thermoswitch plug to the incoming thermoswitchlead (upper assemblies only). Ensure that the connectors for thethree upper assemblies are secure.Publication 2361-5.17 - May 1998Armature Heatsink Assembly Replacement (for 1250 and 1650A, 1395 DC Drives)7Concluding Steps After installing the assembly, replace all Lexan shielding and securethe bridge bay door. Dispose of old parts according to your companyprocedures and local ordinances.Publication 2361-5.17 - May 1998Lexan is a trademark of General Electric Corp.Glastic is a trademark of Glastic, Inc.Publication 2361-5.17 - May 1998P/N 185417© 1998 Rockwell International. All Rights Reserved. Printed in USA。

Rosemount 3144P Temperature Transmitter Quick Star

Quick Start Guide00825-0100-4021, Rev SBMay 2023 Rosemount™ 3144P Temperature TransmitterWith HART® Protocol and Rosemount X-well™ TechnologyQuick Start Guide May 2023ContentsAbout this guide (3)System readiness (5)Verify configuration (6)Set the switches (10)Mount the transmitter (11)Wire and apply power (14)Perform a loop test (19)Safety Instrumented Systems (SIS) (20)Product certifications (21)2Rosemount 3144PMay 2023Quick Start Guide 1 About this guideThis guide provides basic guidelines for installing the Rosemount3144P Transmitter. It does not provide instructions for detailedconfiguration, diagnostics, maintenance, service, troubleshooting,Explosion-proof, Flameproof, or intrinsically safe (I.S.) installations.Refer to the Rosemount 3144P Transmitter Reference Manual formore instructions. The manual and this guide are also availableelectronically on /Rosemount.WARNINGExplosionsExplosions could result in death or serious injury.Installation of device in an explosive environment must be inaccordance with appropriate local, national, and internationalstandards, codes, and practices.Review the Product Certifications section of this document for anyrestrictions associated with a safe installation.Process leaksProcess leaks may cause harm or result in death.Install and tighten thermowells and sensors before applyingpressure.Do not remove the thermowell while in operation.Conduit/cable entriesThe conduit/cable entries in the transmitter housing use a ½–14NPT thread form.When installing in a hazardous location, use only appropriatelylisted or Ex certified plugs, glands, or adapters in cable/conduitentries.Electrical shockElectrical shock can result in death or serious injury.Avoid contact with the leads and terminals. High voltage that may bepresent on leads could cause electrical shock.Quick Start Guide3Quick Start Guide May 2023 WARNINGPhysical accessUnauthorized personnel may potentially cause significant damage toand/or misconfiguration of end users’ equipment. This could beintentional or unintentional and needs to be protected against.Physical security is an important part of any security program andfundamental in protecting your system. Restrict physical access byunauthorized personnel to protect end users’ assets. This is true forall systems used within the facility.4Rosemount 3144PMay 2023Quick Start Guide 2 System readiness2.1 Confirm HART® revision capabilityIf using HART-based control or asset management systems, confirmthe HART capability of those systems prior to transmitter installation.Not all systems are capable of communicating with HART Revision 7Protocol. You can configure the transmitter for either HART Revision5 or 7.For instructions on how to change the HART revision of yourtransmitter, refer to Switch HART revision mode.Quick Start Guide53 Verify configurationThe Rosemount 3144P Transmitter communicates using a Field Communicator (communication requires a loop resistance between 250 and 1100 ohms) or AMS Device Manager.Do not operate when power is below 12 Vdc at the transmitter terminal. Refer to the Rosemount 3144P Transmitter Reference Manual and Field Communicator Reference Manual .3.1 Update the Field Communicator softwareTo fully communicate with the Rosemount 3144P Transmitter, you need the latest Field Communicator Field Device Revision Dev v5 or v7, DD v1 or greater. Transmitters equipped with Rosemount X-well Technology require DD revision 3144P Dev. 7 Rev. 1 or greater to view this functionality.The Device Descriptors are available with new communicators at /Rosemount , or you can download them into existing communicators at any Emerson Service Center.The device descriptors are as follows:•Device in HART 5 mode: Device v5 DDv1•Device in HART 7 mode: Device v7 DDv1To determine if you need to upgrade your device:Figure 3-1: Connecting a Field Communicator to a bench loopA.Power/signal terminalsB.250 Ω ≤ R L ≤ 1100 ΩC.Power supply Procedure1.Connect the sensor.Quick Start Guide May 20236Rosemount 3144PMay 2023Quick Start Guide See the wiring diagram located on the inside of the housingcover.2.Connect the bench power supply to the power terminals ("+"or "-").3.Connect a Field Communicator to the loop across a loopresistor or at the power/signal terminals on the transmitter.The following message will appear if the communicator has aprevious version of the device descriptors (DDs):Upgrade the communicator software to access new XMTR functions.Continue with old description?NoteIf this notice does not appear, the latest DD is installed.If the latest version is not available, the communicator willcommunicate properly, but when the transmitter is configured somenew capabilities may not be visible.To prevent this from happening, upgrade to the latest DD oranswer NO to the question and default to the generic transmitterfunctionality.3.2 Switch HART revision modeIf the HART Protocol configuration tool is not capable ofcommunicating with HART Revision 7, the transmitter will load ageneric menu with limited capability. The following procedure willswitch the HART Revision mode from the generic menu.ProcedureSelect Manual Setup → Device Information → Identification → Message.•To change to HART Revision 5, enter HART5 in the Message field.•To change to HART Revision 7, enter HART7 in the Message field.Quick Start Guide May 20238Rosemount 3144PMay 2023Quick Start GuideQuick Start Guide9Quick Start Guide May 2023 4 Set the switchesThe Rosemount 3144P Transmitter comes with hardware switches toconfigure alarms and lock the device.WARNINGEnclosure covers must be fully engaged to meet explosion-proofrequirements.4.1 Set the switches with an LCD displayProcedure1.Set the loop to manual (if applicable) and disconnect thepower.2.Remove the electronics housing cover.3.Unscrew the LCD display screws and gently slide the meterstraight off.4.Set the alarm and security switches to the desired position.5.Gently slide the LCD display back into place.6.Replace and tighten the LCD display screws to secure the LCDdisplay.7.Reattach housing cover.8.Apply power and set the loop to automatic control.4.2 Set the switches without an LCD displayProcedure1.Set the loop to manual (if applicable) and disconnect thepower.2.Remove the electronics housing cover.3.Set the alarm and security switches to the desired position.4.Reattach housing cover.5.Apply power and set the loop to automatic control.10Rosemount 3144P5 Mount the transmitterMount the transmitter at a high point in the conduit run to preventmoisture from draining into the transmitter housing.5.1 Typical North American installationProcedure1.Mount the thermowell to the process container wall.2.Install and tighten thermowells.3.Perform a leak check.4.Attach any necessary unions, couplings, and extension fittings.Seal the fitting threads with an approved thread sealant, suchas silicone or PTFE tape (if required).5.Screw the sensor into the thermowell or directly into theprocess (depending on installation requirements).6.Verify all sealing requirements.7.Attach the transmitter to the thermowell/sensor assembly.Seal all threads with an approved thread sealant, such assilicone or PTFE tape (if required).8.Install field wiring conduit into the open transmitter conduitentry (for remote mounting) and feed wires into thetransmitter housing.9.Pull the field wiring leads into the terminal side of the housing.10.Attach the sensor leads to the transmitter sensor terminals.The wiring diagram is located inside the housing cover.11.Attach and tighten both transmitter covers.5.2 Typical European installationProcedure1.Mount the thermowell to the process container wall.2.Install and tighten thermowells.3.Perform a leak check.4.Attach a connection head to the thermowell.5.Insert sensor into the thermowell and wire the sensor to theconnection head.The wiring diagram is located inside the connection head.6.Mount the transmitter to a 2-in. (50 mm) pipe or a panel usingone of the optional mounting brackets.7.Attach cable glands to the shielded cable running from theconnection head to the transmitter conduit entry.8.Run the shielded cable from the opposite conduit entry on thetransmitter back to the control room.9.Insert shielded cable leads through the cable entries intothe connection head/transmitter. Connect and tighten cableglands.10.Connect the shielded cable leads to the connection headterminals (located inside the connection head) and tothe sensor wiring terminals (located inside the transmitterhousing).5.3 Install Rosemount X-well TechnologyRosemount X-well Technology is for temperature monitoringapplications and is not intended for control or safety applications.It is available in the Rosemount 3144P Temperature Transmitter ina factory assembled direct mount configuration with a Rosemount0085 Pipe Clamp Sensor. It cannot be used in a remote mountconfiguration.Rosemount X-well Technology will only work as specified with factorysupplied and assembled Rosemount 0085 Pipe Clamp silver tippedsingle element sensor with a 3.2-in. (80 mm) extension length. It willnot work as specified if used with other sensors. Installing and usingthe incorrect sensor will result in inaccurate process temperaturecalculations.ImportantFollow the above requirements and installation best practices belowto ensure that Rosemount X-well Technology works as specified.Follow pipe clamp sensor installation best practices. See Rosemount0085 Pipe Clamp Sensor Quick Start Guide with Rosemount X-wellTechnology specific requirements noted below:Procedure1.Mount the transmitter directly on a pipe clamp sensor.2.Install the transmitter away from dynamic externaltemperature sources, such as a boiler or heat tracing.Inaccurate calculationsMoisture build-up between the sensor and pipe surface or sensor hang-up in assembly can cause inaccurate process temperature calculations.Make sure the pipe clamp sensor tip makes direct contactwith the pipe surface.Refer to installation best practices in Rosemount 0085 PipeClamp Sensor Quick Start Guide to ensure proper sensor to pipe surface contact.3.To prevent heat loss, insulate the sensor clamp assembly and sensor extension up to the transmitter head (½-in. thick minimum with an R-value of > 0.42 m2 x K/W). Apply a minimum of 6-in. (152.4 mm) of insulation on each side of the pipe clamp sensor.Take care to minimize air gaps between insulation and pipe. See Figure 5-1.Figure 5-1: Transmitter with Rosemount X-well Technology installationOver-insulationInsulating the transmitter head may result in longer response times and may damage the transmitter electronics.Do not apply insulation over the transmitter head.4.Although it will be configured that way at the factory, ensure that the pipe clamp RTD sensor is assembled in four-wire configuration.6 Wire and apply power6.1 Wire the transmitterWiring diagrams are located inside the terminal block cover. Table 6-1: Single sensor(1)Emerson provides four-wire sensors for all single-element RTDs. You can use theseRTDs in three-wire configurations by leaving the unneeded leads disconnected and insulated with electrical tape.(2)Transmitter must be configured for a three-wire RTD in order to recognize an RTDwith a compensation loop.Table 6-2: Dual sensorEmerson provides four-wire sensors for all single-element RTDs. To use these RTDs in three-wire configurations, leave the unneeded leads disconnected and insulated with electrical tape This table refers to wiring dual sensors for ΔT and Hot Backup™.6.2 Power the transmitterAn external power supply is required to operate the transmitter.A.Sensor terminals (1–5)B.Power terminalsC.GroundProcedure1.Remove the terminal block cover.2.Connect the positive power lead to the "+" terminal.3.Connect the negative power lead to the "-" terminal.4.Tighten the terminal screws.5.Reattach and tighten the cover.WARNINGEnclosureEnclosure covers must be fully engaged to meet explosion-proof requirements.6.Apply power.6.3 Load limitationsThe power required across the transmitter power terminals is 12 to42 Vdc (power terminals are not rated to 42.4 Vdc).To prevent the possibility of damaging the transmitter, do not allowterminal voltage to drop below 12.0 Vdc when changing theconfiguration parameters.Figure 6-1: Load limitationMaximum load = 40.8 x (supply voltage - 12.0) without transientprotection (optional).A.HART and analog operating rangeB.Analog only operating range6.4 Ground the transmitter6.4.1 Ungrounded thermocouple, mV, and RTD/ohm inputsEach process installation has different requirements for grounding.Use the grounding options recommended by the facility for thespecific sensor type or begin with grounding option 1 (the mostcommon).Ground the transmitter: option 1Emerson recommends this option for ungrounded transmitterhousing.Procedure1.Connect signal wiring shield to the sensor wiring shield.2.Ensure the two shields are tied together and electricallyisolated from the transmitter housing.3.Ground shield at the power supply end only.4.Ensure that the sensor shield is electrically isolated from thesurrounding grounded fixtures.A.Remote sensor housingB.SensorC.TransmitterD.Shield ground pointsGround the transmitter: option 2Emerson recommends this method for grounded transmitter housing.Procedure1.Connect sensor wiring shield to the transmitter housing.Do this only if the housing is grounded.2.Ensure that the sensor is electrically isolated from surroundingfixtures that may be grounded.3.Ground signal wiring shield at the power supply end.A.Remote sensor housingB.TransmitterC.SensorD.Shield ground partsGround the transmitter: option 3Procedure1.Ground sensor wiring shield at the sensor, if possible.2.Ensure the sensor wiring and signal wiring shields areelectrically isolated from the transmitter housing and othergrounded fixtures.3.Ground signal wiring shield at the power supply end.A.SensorB.TransmitterC.Shield ground points6.4.2 Ground thermocouple inputsProcedure1.Ground sensor wiring shield at the sensor.2.Ensure the sensor wiring and signal wiring shields areelectrically isolated from the transmitter housing and othergrounded fixtures.3.Ground signal wiring shield at the power supply end.A.Sensor wiresB.TransmitterC.Shield ground pointD.4–20 mA loop7 Perform a loop testThe loop test verifies transmitter output, loop integrity, andoperation of any recorders or similar devices installed in the loop.The following procedures are for the device dashboard - devicerevisions 5 and 7, DD v1.7.1 Initiate a loop testProcedure1.Connect an external ampere meter in series with thetransmitter loop (so the power to the transmitter goesthrough the meter at some point in the loop).2.From the Home screen, select 3 Service Tools → 5 Simulate → 1Perform Loop Test.The communicator displays the loop test menu.3.Select a discrete milliampere level for the transmitter tooutput.a)At Choose Analog Output, select 1 4 mA or 2 20 mA. Ifyou want to enter a different value, select 4 Other tomanually input a value between 4 and 20 milliamperes.b)Select Enter to show the fixed output.c)Select OK.4.In the test loop, check that the transmitter's actual mA outputand the HART mA reading are the same value.If the readings do not match, either the transmitter requiresan output trim or the current meter is malfunctioning.After completing the test, the display returns to the loop testscreen where you can choose another output value.5.To end the loop test, select 5 End and Enter.7.2 Initiate simulation alarmProcedure1.From the Home screen, select 3 Service Tools → 5 Simulate → 1Perform Loop Test → 3 Simulate Alarm.The transmitter will output the alarm current level based onthe configured alarm parameter and switch settings.2.Select 5 End to return the transmitter to normal conditions.8 Safety Instrumented Systems (SIS) For safety certified installations, refer to the Rosemount 3144PReference Manual. The manual is available electronically on/Rosemount. You can also contact an Emersonrepresentative for the manual.9 Product certificationsRev 2.219.1 European Directive informationA copy of the EU Declaration of Conformity can be found at theend of the Quick Start Guide. The most recent revision of the EUDeclaration of Conformity can be found at /Rosemount.9.2 Ordinary location certificationAs standard, the transmitter has been examined and tested todetermine that the design meets the basic electrical, mechanical,and fire protection requirements by a nationally recognized testlaboratory (NRTL) as accredited by the Federal Occupational Safetyand Health Administration (OSHA).9.3 North America9.3.1 E5 USA explosionproof, dust-ignitionproof, and nonincendiveCertificate FM16US0202XStandards FM Class 3600: 2011, FM Class 3611: 2004, FM Class3615: 2006, FM Class 3810: 2005, ANSI/NEMA 250: 1991,ANSI/ISA 60079-0: 2009, ANSI/ISA 60079-11: 2009 Markings XP CL I, DIV 1, GP A, B, C, D; T5(-50 °C ≤ T a≤ +85 °C);DIP CL II/III, DIV 1, GP E, F, G; T5(-50 °C ≤ T a≤ +75 °C);T6(-50 °C ≤ T a≤ +60 °C); when installed per Rosemountdrawing 03144-0320;NI CL I, DIV 2, GP A, B, C, D; T5(-60 °C ≤ T a≤ +75 °C);T6(-60 °C ≤ T a≤+60 °C); when installed per Rosemountdrawing 03144-0321, 03144-5075.9.3.2 I5 USA intrinsic safety and nonincendiveCertificate FM16US0202XStandards FM Class 3600: 2011, FM Class 3610: 2010, FM Class3611: 2004, FM Class 3810: 2005, ANSI/NEMA 250: 1991,ANSI/ISA 60079-0: 2009, ANSI/ISA 60079-11: 2009 Markings IS CL I/II/III, DIV 1, GP A, B, C, D, E, F, G; T4(-60 °C ≤ T a≤+60 °C);IS [Entity] CL I, Zone 0, AEx ia IIC T4(-60 °C ≤ T a≤ +60 °C);NI CL I, DIV 2, GP A, B, C, D; T5(-60 °C ≤ T a≤ +85 °C);T6(-60 °C ≤ T a≤ +60 °C); when installed per Rosemountdrawing 03144-0321;9.3.3 I6 Canada intrinisic safety and Division 2Certificate1242650Standards CSA Std C22.2 No. 25-17, CAN/CSA-C22.2 No. 94.2:20,CSA Std C22.2 No. 213-17, CAN/CSA-C22.2 No. 60079-0:2019, CAN/CSA-C22.2 No. 60079-11: 2014, CAN/CSA-C22.2 No. 61010-1-12, UPD1: 2015, UPD2: 2016;Markings Intrinsically Safe for Class I, Groups A, B, C, D; Class II,Groups E, F, G; Class III;IS[Entity] Ex ia IIC T4, Ex ia IIIC T94C T4(-60°C≤Ta≤+60°C);[HART only zone markings]: Intrinsically Safe for Class IZone 0 Group IIC; T4(-50 °C ≤ T a≤ +60 °C); Type 4X;Suitable for Class I, Div. 2, Groups A, B, C, D;[HART only zone markings]: Suitable for Class I Zone 2Group IIC; T6(-60 °C ≤ T a≤ +60 °C); T5(-60 °C ≤ T a≤ +85°C); when installed per Rosemount drawing 03144-5076.9.3.4 K6 Canada explosionproof, intrinsic safety, and Division 2Certificate1242650Standards CAN/CSA C22.2 No. 0-M91 (R2001), CSA Std C22.2 No.25-1966, CSA Std C22.2 No. 30-M1986; CAN/CSA-C22.2No. 94-M91, CSA Std C22.2 No. 142-M1987, CAN/CSA-C22.2 No. 157-92, CSA Std C22.2 No. 213-M1987 Markings Explosionproof for Class I, Groups A, B, C, D; Class II,Groups E, F, G; Class III;[HART only zone markings]: Suitable for Class I, Zone 1,Group IIC; Intrinsically Safe for Class I, Groups A, B, C, D;Class II, Groups E, F, G; Class III;[HART only zone markings]: Suitable for Class I, Zone 0,Group IIC; T4(-50 °C ≤ T a≤ +60 °C); Type 4X; Suitable forClass I, Div. 2, Groups A, B, C, D;[HART only zone markings]: Suitable for Class I, Zone 2,Group IIC; T6(-60 °C ≤T a≤ +60 °C); T5(-60 °C ≤ T a≤ +85°C); when installed per Rosemount drawing 03144-5076.9.4 Europe9.4.1 E1 ATEX flameproofCertificate DEKRA 19ATEX0076 XStandards EN IEC 60079-0: 2018, EN 60079-1: 2014Markings II 2 G Ex db IIC T6…T1 Gb, T6(-60 °C ≤ Ta≤ +70 °C),T5…T1(-60 °C ≤ T a≤ +80 °C)Specific Conditions of Use (X):1.Flameproof joints are not intended for repair.2.Non-standard paint options may cause risk from electrostaticdischarge. Avoid installations that cause electrostatic build-upon painted surfaces and only clean the painted surfaces with adamp cloth. If paint is ordered through a special option code,contact the manufacturer for more information.Additional Specific Conditions of Use (X) when “XA” designation isordered:Guard DIN style sensors against impacts greater than 4J.junction box housing9.4.2 I1 ATEX Intrinsic SafetyCertificate BAS01ATEX1431X [HART]; Baseefa03ATEX0708X[Fieldbus]Standards EN IEC 60079-0: 2018; EN 60079-11:2012Markings HART: II 1 G Ex ia IIC T5/T6 Ga; T6(-60 °C ≤ Ta≤ +50°C), T5(-60 °C ≤ T a≤ +75 °C)Fieldbus: II 1 G Ex ia IIC T4 Ga; T4(-60 °C ≤ T a≤ +60°C)See Table 9-6 for entity parameters.Special Conditions for Safe Use (X):1.When fitted with the transient terminal options, theequipment is not capable of passing the 500 V insulation test.This must be taken into account during installation.2.The enclosure may be made from aluminum alloy with aprotective polyurethane paint finish; however, care should betaken to protect it from impact or abrasion when located inZone 0.9.4.3 N1 ATEX Type nCertificate BAS01ATEX3432X [HART]; Baseefa03ATEX0709X[Fieldbus]Standards EN IEC 60079-0:2018, EN 60079-15:2010Markings HART: II 3 G Ex nA IIC T5/T6 Gc; T6(-40 °C ≤ Ta≤ +50°C), T5(-40 °C ≤ T a≤ +75 °C);Fieldbus: II 3 G Ex nA IIC T5 Gc; T5(-40 °C ≤ T a≤ +75°C);Special Condition for Safe Use (X):When fitted with the transient terminal options, the equipment is notcapable of withstanding the 500 V electrical strength test as definedin clause 6.5.1 of EN 60079-15: 2010. This must be taken into accountduring installation.9.4.4 ND ATEX dustCertificate DEKRA 19ATEX0076 XStandards EN IEC 60079-0:2018, EN 60079-31:2014Markings II 2 D Ex tb IIIC T130 °C Db, (-60 °C ≤ Ta≤ +80 °C) Specific Condition of Use (X):Non-standard paint options may cause risk from electrostaticdischarge. Avoid installations that cause electrostatic build-up onpainted surfaces and only clean the painted surfaces with a dampcloth. If paint is ordered through a special option code, contact themanufacturer for more information.Additional Specific Condition of Use (X) when “XA” designation isordered:The spring loaded adapter style sensors and DIN style sensors mustbe installed in a thermowell to maintain Ex tb protection.junction box housing9.5 International9.5.1 E7 IECEx flameproofCertificate IECEx DEK 19.0041XStandards IEC 60079-0:2017, IEC 60079-1:2014Markings Ex db IIC T6…T1 Gb, T6(-60 °C ≤ T a≤ +70 °C), T5…T1(-60°C ≤ T a≤ +80 °C);Specific Conditions of Use (X):1.Flameproof joints are not intended for repair.2.Non-Standard Paint options may cause risk from electrostaticdischarge. Avoid installations that cause electrostatic build-upon painted surfaces, and only clean the painted surfaces with adamp cloth. If paint is ordered through a special option code,contact the manufacturer for more information.Additional Specific Conditions of Use (X) when “XA” designation isordered:Guard DIN Style sensors against impacts greater than 4J.junction box housing.Additionally Available with Option K7:IECEx DustCertificate IECEx DEK 19.0041XStandards IEC 60079-0:2017 and IEC 60079-31:2013Markings Ex tb IIIC T130 °C Db, (-60 °C ≤ T a≤ +80 °C);Specific Conditions of Use (X):Non-Standard Paint options may cause risk from electrostaticdischarge. Avoid installations that cause electrostatic build-up onpainted surfaces, and only clean the painted surfaces with a dampcloth. If paint is ordered through a special option code, contact themanufacturer for more information.Additional Specific Conditions of Use (X) when “XA” designation isordered:The spring loaded adapter style sensors and DIN style sensors mustbe installed in a thermowell to maintain Ex tb protection.junction box housing.9.5.2 I7 IECEx intrinsic safetyCertificate IECEx BAS 07.0002X [HART]; IECEx BAS 07.0004X[Fieldbus]Standards IEC 60079-0: 2017; IEC 60079-11: 2011Markings HART: Ex ia IIC T5/T6 Ga; T6(-60 °C ≤ T a≤ +50 °C), T5(-60°C ≤ T a≤ +75 °C);Fieldbus: Ex ia IIC T4 Ga; T4(-60 °C ≤ T a≤ +60 °C)See Table 9-6 for entity parameters.Special Conditions for Safe Use (X):1.When fitted with the transient terminal options, theequipment is not capable of passing the 500 V electricalstrength test as defined in Clause 6.3.13 of IEC 60079-11: 2011.This must be taken into account during installation.2.The enclosure may be made from aluminum alloy with aprotective polyurethane paint finish; however, care should betaken to protect it from impact or abrasion when located inZone 0.9.5.3 N7 IECEx Type nCertificate IECEx BAS 07.0003X [HART]; IECEx BAS 07.0005X[Fieldbus]Standards IEC 60079-0:2017, IEC 60079-15:2010Markings HART: Ex nA IIC T5/T6 Gc; T6(-40 °C ≤ T a≤ +50 °C), T5(-40°C ≤ T a≤ +75 °C);Fieldbus: Ex nA IIC T5 Gc; T5(-40 °C ≤ T a≤ +75 °C);Special Condition for Safe Use (X):When fitted with the transient terminal options, the equipment is notcapable of passing the 500 V electrical strength test as defined inclause 6.5.1 of IEC 60079-15: 2010. This must be taken into accountduring installation.9.6 Brazil9.6.1 E2 Brazil flameproof and dustCertificate UL-BR 21.1296XStandards ABNT NBR IEC 60079-0:2020; ABNT NBR IEC60079-1:2016; ABNT NBR IEC 60079-31:2014Markings Ex db IIC T6...T1 Gb; T6 (-60 °C ≤ T a≤ +70 °C); T5...T1 (-60°C ≤ T a≤ +80 °C)Ex tb IIIC T130 °C Db; (-60 °C ≤ T a≤ +80 °C)Special Conditions for Safe Use (X):1.Flameproof joints are not intended for repair.2.Non-standard paint options may cause risk of electrostaticdischarge. Avoid installations that cause electrostatic build-upon painted surfaces and only clean the painted surfaces with adamp cloth. If paint is ordered through a special option code,contact the manufacturer for more information.Additional Special Conditions for Safe Use (X) when “XA”designation is ordered:1.Guard DIN Style sensors against impacts greater than 4J.2.The spring loaded adapter style sensors and DIN style sensorsmust be installed in a thermowell to maintain Ex tb protection.。

nVent RAYCHEM WinterGard H910 水抗拓扑热溶液电缆连接套件说明书

Our powerful portfolio of brands:CADDY ERICO HOFFMAN RAYCHEM SCHROFF TRACER©2020 nVent. All nVent marks and logos are owned or licensed by nVent Services GmbH or its affiliates. All other trademarks are the property of their respective owners. nVent reserves the right to change specifications without notice.RAYCHEM-DS-H 60886-H 910-EN-2003910ABSTRACTThe nVent RAYCHEM WinterGard H 910 Waterproof Splice and Tee Kit is for use with nVent RAYCHEM WinterGard self-regulating heat tracing cables to make splice, tee, and end seal connections. The kit contains materials for one end seal connection and either one splice or one tee connection. This kit does not provide a power connection; use an nVent RAYCHEM WinterGard H 900 or H 908 Power Connection Kit (for 120V cables only) to complete an installation that complies with warranty and national electrical code requirements.FEATURES• E nables one end seal connection and either one splice or one tee connection for WinterGard cables• Suitable for wet environments (do not submerge)• UL and CSA listedSPECIFICATIONS Reference Code H 910Short Description Waterproof Splice and Tee Kit Catalog Number 217793-000UPC 715629000330Applications Pipe Freeze Protection, Roof & Gutter De-IcingCategory W interGard Splice & Tee Connection Kits Package TypePoly bagPackage Size (LxWxD) 10” x 6” x 2”Package Weight 0.3 lb.Inventory StatusFI (Factory Inventoried)The minimum installation temperature for this kit is 0°F (–18°C). See the WinterGard Application and Design Guide (H53585), H900, or H908 installation instructions for design information. For additional technical support call nVent at (800) 545-6258.KIT CONTENTSItem Qty Description A 2 Insulated bus wire crimps B 1 Uninsulated braid crimps C 3 Cable ties D 6 Mastic stripsE 1 Heat-shrinkable capF 1 Heat-shrinkable tube (6 inch long, 1 inch dia.)G 2 Black cloth tape (6 inch long)H 1 Clamp tie I1End seal718K Pipe Heating Cable or 877Z De-icing and Snow Melting EquipmentH910This component is an electrical device that must be installed correctly to ensure proper operation and toprevent shock or fire. Read these important warnings and carefully follow all the installation instructions.• To minimize the danger of fire from sustained electrical arcing if the heating cable is damaged or improperly installed, and to comply with the requirements of nVent, agency certifications, and national electrical codes, ground-fault equipment protection must be used. Arcing may not be stopped by conventional circuit breakers.• Bus wires will short if they contact each other. Keep bus wires separated.• Keep components and heating cable ends dry before and during installation.• The black heating cable core is conductive and can short. It must be properly insulated and kept dry.• Component approvals and performance are based on the use of nVent-specified parts only. Do not use substitute parts or vinyl electrical tape.• Leave these instructions with end user for reference and future use.HEALTH HAZARD : Overheating heat-shrinkable tubes will produce fumes that may cause irritation. Use adequate ventilation and avoid charring or burning. Consult MSDS RAY3122 for further information.CHEMTREC 24-hour emergency telephone: (800) 424-9300Non-emergency health and safety information: (800) 545-6258.The instructions are shown for a tee connection. Splice connections are done the same way, without the third heating cable section.2 | | 34 | | 56 | | 7North AmericaTel +1.800.545.6258 Fax +1.800.527.5703 **********************Europe, Middle East, AfricaTel +32.16.213.511Fax +32.16.213.604**********************Asia PacificTel +86.21.2412.1688Fax +86.21.5426.3167*************************Latin AmericaTel +1.713.868.4800Fax +1.713.868.2333**********************。

高效选择热沉淀指南说明书

(603) 528-1478e-mail:*************With the increase in heat dissipation from microelec-tronic devices and the reduction in overall form factors,thermal managementa more and more impor-tant element of electronic product design. Both the per-formance reliability and life expectancy of electronic equip-ment are inversely related to the component temperature of the equipment. The relationship between the reliability yand the operating temperature of a typical silicon semi-conductor device shows that a reduction in the tempera-ture corresponds to an exponential increase in the reliabil-ity and life expectancy of the device. Therefore, long life and reliable performance of a component may be achieved by effectively controlling the device operating temperature within the limits set by the device design engineers.Heat sinks are devices that enhance heat dissipation from a hot surface, usually the case of a heat generating component, to a cooler ambient, usually air. For the fol-lowing discussions, air is assumed to be the cooling fluid. In most situations, heat transfer across the interface bet weenthe solid surface and the coolant air is the lead efficientwithin the system, and the solid-air interface representsthe greatest barrier for heat dissipation. A heat sink low-ers this barrier mainly by increasing the surface area that is in direct contact with the coolant. This allows moreheat to be dissipated and/or lowers the device operatingtemperature.The primary purpose of a heat sink is tomaintain the device temperature below the maximum al-lowable temperature specified by the device manufacturer.Thermal Circuit Before discussing the heat sink selection process, it is necessary to define common terms and establish the con-cept of a thermal circuit. The objective is to provide basic fundamentals of heat transfer for those readers who are not familiar with the subject. Notations and definitions of the terms are as follows:Q :T j :total power or rate of heat dissipation in W,represents the rate of heat dissipated by the electronic component during operation. For the purpose of selecting a heat sink, the maximum operating power dissipation is used.maximum junction temperature of the devicein 0 C. Allowable T j values range from 115°C in typical microelectronic applications to aahigh as 180° C for some electronic control devices,T = ::Figure 1: Thermal Resistance CircuitIn” special and military applications, 65°C to 80°C are not uncommon.case temperature of the device in 0 C. Since thecase temperature of a device depends on the location of measurement, it usually represents the maximum local temperature of the case.sink temperature in 0 C. Again, this represents the maximum temperature of a heat sink at the location closest to the device.ambient air temperature in 0 C.Using temperatures and the rate of heat dissipation, aquantitative measure locations of a thermal of thermal resistance of heat transfer efficiency across twocomponent can be expressed in termsR, defined as A TR =—Q where AT is the temperature difference between the two locations. The unit of thermal resistance is in 0 C/W, in-dicating the temperature rise per unit rate of heat dissipa-tion. This thermal resistance is analogous to the electricalresistance R e , given by Ohm’s law:with AV being the voltage difference and I the current.Consider a simple case where a heat sink is mounted ona device packagedrawn,the case then across the interface into the heat sink, and finally dissipated from the heat sink to the air stream.The thermal resistance between the junction and the case of a device is defined asThis resistancethough theis beyond the user’s ability to alter or control.Similarly, case-to-sink and sink-to-ambient resistancesare defined asRQ Qrespectively, Here,Ris the heat-sink thermai resistance.Obviously, the total junction-to-ambient resistance is thesum of all three resistances:Required Heat-Sink Thermal ResistanceTo begin the heat sink selection, the first step is to de-termine the heat-sink thermal resist ante required to satisfy the thermal criteria of the component. By rearranging the previous equation, the heat-sink resistance can be easily obtained asRT jR jcIn this expression, T j , Qandanddepends on the surface fin-ish, flatness, applied mounting pressure, contact area, and,of course, the type of interface material and its thickness.Precise value of this resistance, even for a given type of material and thickness, is difficult to obtain, since it mayvary widely with the mounting pressure and other case dependent parameters.However, more reliable data can be obtained directly from material manufacturers or from heat-sink manufacturers. Typical values for common in-terface materials are tabulated in Table 1.Table 1: Thermal Properties of Interface18980.0100.0300.0300.0080.0140.0090.0100.0190.0740.010”0.008Thicknessinches 0.0020.0020.0050.0040.0060.0050.0020.0050.0200.0080.006Resistancebecomes thethermal resistance of a heat sink for the application. In other words, the thermal resistance value of a chosen heat sink for the application has to be equal to or less thanthe above570) when the induced air flow velocity exceeds 1 to 2 m/s (200 to 4004.5.- ambient)Figure 2: Cost versus Required Thermai Resistance fin height-to-gap aspect ratio of 20 to 40, greatly in-creasing the cooling capacity without increasing vol-ume requirements.Castings: Sand, lost core and die casting processes are available with or without vacuum assistance, in aluminum or copper/bronze. This technology is used in high density pin fin heat sinks which provide max-imum performance when using impingement cooling.Folded Fins: Corrugated sheet metal in either alu-minum or copper increases surface area and, hence,the volumetric performance. The heat sink is then at-tached to either a base plate or directly to the heating surface via epoxying or brazing. It is not suitable for high profile heat sinks due to the availability and from the fin efficiency point of view. However, it allows to fabricate high performance heat sinks in applications where it is impractical or impossible to use extrusions or bonded fins.Figure 2 shows the typical range of cost functions for dif-ferent types of heat sinks in terms of the required thermal resistance.The performance of different heat-sink types varies dra-matically with the air flow through the heat sink. To quan-tify the effectiveness of different types of heat sinks, the volumetric heat transfer efficiency can be defined aswhere,is the average tem-perature difference between the heat sink and the ambient air. The heat transfer efficiencies have been measured fora wide range of heat-sink configurations, and their are listed in Table 4.Table 4:ated with additional costs in either material or manufac-turing, or both.Thermal Performance GraphPerformance graphs typical of those published by heat-sink vendors are shown in Fig. 3. The graphs are a compos-ite of two separate curves which have been combined into a single figure. It is assumed that the device to be cooled is properly mounted, and the heat sink is in its normally used mounting orientation with respect to the direction of air flow. The first plot traveling from the lower left to the upper right is the natural convection curve of the heat-sinktemperature rise,is linearly propor-tional to Q, hence a function of Q.One can use the performance graphs to identify the heat sink and, for forced convection applications, determine theminimum flow velocity that satisfy the thermal require-ments. If the required thermal resistance in a forced con-vection application is 8° C/ W, for example, the above sam-ple thermal resist ante versus flow velocity curve indicates that the velocity needs to be at or greater than 2,4 m/s(470 lfm). For natural convection applications, the re-quired thermal resistance R ,a can be multiplied by Q toyield the maximum allowable at the same Q,The readers are reminded that the natural convection curves aasume an optimal orientation of the heat sink with respect to the gravity. Also, the flow velocity in the forced convection graph represents the approach flow veloc-it y without accounting for the effect of flow bypass. Therehave been a limited number ofTablecon-sultation on this subject readers are referred to the citedreferences.When a device is substantially smaller than the baseplate of a heat sink, there is an additional thermal resis-tance, called the spreading resistance, that needs to beconsidered in the selection process. Performance graphsgenerally assume that the heat is evenly distributed overthe entire base area of the heat sink, therefore,of the total heat-sink resistance, andcan be estimated by using the simple analytical expressiondeveloped in Reference 4.controlled and is not affected by the altitude change, theindoor air pressure does change with the aititude. Sincemany electronic systems are installed at anmainly due to the lower air density caused by theForexample, in order to determine the actual thermal perfor-mance of a heat sink at altitudes other than thereauired thermal resistance.ReferencesSea Level 1.0012000)0.75Aavid Engineering, Inc.,EDS #117,InterfaceJanuary 1992.116,。

XENON (XE) 系列 AMD Socket SP5 冷却器安装指南说明书

Figure 1Figure 2Figure 3Figure 4Take out the heatsink from its packing box. Before installing the heat sink, please check that heat sink must be properly oriented to the system cooling air flow direction (Figure 1 & Figure 2).1.XENON (XE) SERIES – Assembly Guide forAMD Socket SP5 CoolersRemove the protection cover of thermal interface material (TIM) or thermal grease. The required amount of TIM has been pre-applied on the bottom of the heat sink. Inspect pre-applied TIM for any damage.Place the heat sink directly on top of the CPU (Figure 3) so that the six heat sink mounting screws are aligned with and seated on the six heat sink mounting studs or nut standoffs on the socket stiffener frame. The heat sink must be properly oriented to the system cooling air flow direction. Please note that the heat sink cooling fan should not be attached to the heat sink body when tightening the six heat sink mounting screws.Use a screwdriver with Torx T20 bit and adjust the screwdriver torque setting to 12.5~15.0 kgf-cm (10.8~13.0 lbf-in). Before turning on the screwdriver, make sure that the screwdriver bit is fully engaged in the cavity of the heat sink mounting screw head. Keep heat sink mounting screw vertical during installations.Tighten the two diagonal heat sink mounting screws, i.e. the #1 and #2 screws (Figure 4) completely tighten screws one-at-a-time Then do the same with the remaining four diagonal heat sink mounting screws.2.3.4.5.Figure 5Figure 66.7.8.Follow the diagonal installation pattern on all six heat sink mounting screws to ensure that the bottom of the heat sink is properly seated on the CPU and to prevent the heat sink from tilting.For XE04 series, adjust the screwdriver torque setting to 5.0~4.0 kgf-cm (4.3~3.5 lbf-in).install the heat sink cooling fan and holder assembly on the heat sink body and then tighten the single locking screw on top of the fan holder (Figure 5 & Figure 6).Connect cooling fan connector to the fan header labeled for CPU on the motherboard.Warranty InformationNO.G1*******Additional info & contactsThis product has a limited 1 year warranty in North America and Australia.For information on warranty periods in other regions, please contact your reseller or SilverStone authorized distributor.本产品自购买之日起，于中国地区（不包含澳门，香港特别行政区）享有一年有限责任保固（部分产品为二年，三年或五年）。

多塔型太阳能集中式电力生成机的无线仪器和无线控制网络说明书

Wireless Instrument and Wireless Control Network for Multi-tower CSP PowerPlantLiguo Hu a, Caiyong Li bNo. 6, Jianhua North Street, Shijiazhuang city, Hebei province, Chinaa*************.cn,b***************Abstract—In this paper, one type of multi-tower CSP power plant’s instrument configuration and function for heliostats, solar thermal receivers, steam and water pipes is presented. Wireless instrument and wireless network configuration are developed based on the character of the instrument configuration. Each type of wireless instrument and its detail application in multi-tower CSP power plant is described. Function and configuration of each type of wireless network equipment, such as wireless multi-function node, every type of wireless adaptor, handheld, wireless device manager is also presented.Keywords-multi-tower, CSP power plant, industrial wireless network, wireless instrumentI.I NTRODUCTIONThe areas covered by a tower type CSP power plant is very large (about 1~10 square kilometers). There is no large object that may stop wireless communication or electric magnetic interference source such as big power motors in the heliostats field.Wireless instrument and wireless network [1] are suitable for the heliostats field which can save large amount of control cable, signal cable and communication cable (thousands kilometers of cable can be saved for one CSP power plant). And cable related work such as erection, commissioning will be saved too. The total erection period of CSP power plant will be reduced dramatically. The faults caused by cable mechanical damage or rodent biting can be reduced to minimum.One type of multi-tower CSP power plant process configuration is presented in this paper as following: heat receiver filled with high purity of graphite located on the top of each tower, and there are some heliostats arranged under the tower. The heliostats reflect and concentrate the sunrays to the cavity at the bottom of the heat receiver on the top of tower. The graphite in the heat receiver will be heated by the sunrays to very high temperature up to 800℃. The graphite then can heat the feed water and steam pipes buried in the graphite to generate high temperature steam to drive the steam turbine generator to send out electric power.This type of multi-tower CSP power plant heliostats field’s instrument and control equipment can be realized by wireless instrument or wireless adaptors to connect with central control server of heliostats field. The mainequipment connect with the wireless network are heatreceiver systems, heliostats and meteorological station etc.II.H EAT R ECEIVER M EDIUM T EMPERATUREM ONITORINGHeat receiver medium (graphite) in multi-tower CSPpower plant must operate in proper temperature range. Toolow temperature will result in no proper temperature steamavailable for steam turbine generator running. Too hightemperature will endanger the safety operation of the system such as heat receiver medium destroy, heatexchange pipe destroy or instrument & control equipmentdestroy etc.Heat receiver medium temperature monitoringshall also provide input for heat storage calculation. Theheat storage calculation result can be used for selection of operation mode of CSP power plant. The followings arethe main temperature monitoring items:1) Heat receiver cavity temperature monitoring;2) Heat receiver medium temperature (temperaturegradient) monitoring;3) Heat receiver output steam temperature monitoringand control.The above temperature monitoring shall all be done bywireless temperature transmitters.Heat receiver cavity temperature monitoring is of mostimportant. It has the following main function:1) Measure the solar energy input;2) Control heliostats operation.When heat receiver cavity temperature reach its highlimit (heat receiver’s energy storage reach its high limit),all or part of the heliostats shall be defocused (direct some of the hel iostats skywards) to avoid heat receiver medium overheated. If the heat receiver is producing steam,part of heliostats shall be defocused to make the energyinput and output of the heat receiver equal.If the heatreceiver is not producing steam, all of heliostats shall bedefocused.III.M ETEOROLOGICAL S TATION O F CSP P OWERP LANTThe meteorological station of CSP power plant mainlymeasures the meteorological parameter near the ground: z Direct Normal solar Irradiance (DNI)z Wind speedInternational Conference on Civil, Materials and Environmental Sciences (CMES 2015)z Wind directionz Air temperaturez Air humidityz Cloud amountz Amount of precipitationThe above parameter shall be sampled every minute at least.According to the interface configuration of the meteorological station, wireless Modbus TCP / RTU adaptor or wireless HART adaptor may be used to transfer the meteorological parameter wirelessly to central control server of heliostats field. City or national meteorological stations’ data may also send to central control server wirelessly to obtain upper air meteorological parameter for CSP power plant control purpose.IV.H EAT RECEIVER STEAM TEMPERATURE CONTROLAND INSTRUMENT CONFIGURATIONHeat receiver internal medium temperature will drop during steam generation process without enough solar energy input (the heat energy in heat receiver medium transfer to steam). The temperature difference between heat receiver medium and feed water decreases in this process. To maintain constant steam temperature required by the steam turbine generator, the feed water flow rate must be reduced too. The heat receiver steam temperature shall be controlled by modulating the feed water flow rate through the heat receiver.The relation of feed water flow rate and heat receiver medium temperature is approximately linear relation.The following instrument configured for this system:z Feed water temperature (Resistant temperature detector), wireless temperature transmitters adopted;z Steam temperature (Thermocouple), wireless temperature transmitters adopted;z Feed water flow rate modulating valve, wireless multi-function combined adaptor adopted;z Feed water pressure, wireless pressure transmitters adopted;z Steam pressure, wireless pressure transmitters adopted.V.H ELIOSTAT C ONTROL A ND I NSTRUMENTC ONFIGURATIONEach heliostat is equipped one field controller and two high precision driving motors and their control module [2]. Driving motors usually powered by 48VDC with solid limit switches. The function of field controller can also be carried by central control server of heliostats field and heliostat equipped with driving motors and their control module. These two configurations have different network communication load and control logic calculation load distribution and should be selected based on cost and technical analysis.Heliostat can equipped with wireless multi-function combined adaptor for heliostat without field controller or wireless Modbus TCP / RTU adaptor (or wireless HART adaptor)for heliostat with field controller. The field controller of heliostat carries out task such as driving motor position command calculation, state monitoring etc. These functions can be carried out by central control server of heliostats field for heliostat without field controller. Heliostat can equipped with wireless mirror position transmitters based on actual control need to monitor mirror position in a real time manner.VI.W IRELESS C ONTROL N ETWORK S TRUCTURE A NDC ONFIGURATIONWireless multi-function node is arranged on top of each heat receiver tower and the node communicates with heliostats, transmitters etc. belong to this heat receiver tower.Wireless multi- function node on steam turbine generator house communicates with the central control server of heliostats field. All of the wireless multi-function nodes form the backbone of the wireless control network. Wireless multi-function nodes and other wireless equipment can be powered locally by heliostat driving motor power supply.Wireless instrument and wireless equipment can set some parameter s according to control requirement such as resolution rate, gain of antenna etc. Wireless instrument and wireless equipment can communicate with wireless multi-function nodes directly or communicate with wireless multi-function nodes through other wireless instrument or wireless equipment.VII.W IRELESS D EVICE M ANAGERSWireless device manager is a platform based on web pages that manage the wireless network, wireless instrument and wireless equipment in the CSP power plant. Wireless device manager has internal fire wall and all necessary security and management software.Wireless device manager’s main functions list below:1) Diagnose wireless network communication: diagnose and manage the wireless communication of the equipment within the wireless network; display wireless communication state and network topological structure; detect the location and tag of the faulty wireless instrument and equipment for maintaining.2) Support remote configures, calibration and maintenance.3) Manage wireless network security.4) Remote access through PC or handheld equipment with correct authorization and proper security measures.Wireless device manager can be arranged in central control server of heliostats field in the CSP power plant or in special security server.VIII.W IRELESS I NSTRUMENT A ND E QUIPMENTC ONFIGURATIONWireless instrument and equipment usually support 1 second resolution uttermost.The resolution rate can also set to 5 second, 10 second, 1 minute or longer. Wireless transmitters’ and wireless adaptors’ for heliostats and resolution can set to 1 second, and 1 minute for meteorological station.Heat receiver medium wireless temperature transmitters’resolution can set to 1 minute orlonger for medium temperature changes very slowly with large heat capacity of medium. But wireless transmitters on feed water and steam pipes shall set to the highest resolution that the equipment support.The outdoor wireless instrument and wireless equipment shall have a shell protection rate of IP66 for high pressure water cleaning of the mirrors.Wireless instrument and wireless equipment in hazardous areas shall have a certification suitable to relative hazardous area.Heat protection for wireless transmitters and wireless multi-function node shall be done to prevent concentrated sunray spot irradiation on them. The erection location of them should be free of concentrated sunray spot irradiation for the best. The outdoor wireless equipment shall be equipped with surge protectors. And the surge protectors’ grounding terminal shall be grounded safely. Other necessary lightning protection measures shall be taken to consideration to protect outdoor wireless equipment from lightning.IX.M AIN C ATEGORIES O F W IRELESS I NSTRUMENTA ND W IRELESS E QUIPMENT I N CSP P OWER P LANT1)Wireless pressure transmitters: including gauge pressure and absolute pressure, accuracy:±0.075%. Wireless pressure transmitters are suitable for various pipes pressure measurement and data acquisition.Wireless pressure transmitters are mainly used for heat receiver feed water and steam pressure measurement in CSP power plant.2) Wireless temperature transmitters: measure and transmit the various temperature measurement points in power plant. Wireless temperature transmitters are suitable for various pipes temperature, tanks temperature and metal temperature measurement and data acquisition. Wireless temperature transmitters are mainly used for heat receiver feed water and steam temperature, heat receiver medium & cavity temperature measurement in CSP power plant.3) Wireless difference pressure / flow transmitters: measure and transmit the various difference pressure / flow measurement points in power plant with accuracy: ±0.075%.Wireless flow transmitters are mainly used for heat receiver feed water flow and plant makeup water flow measurement in CSP power plant.4) Wireless multi-function combined adaptor: sample the wired signals and transmit them wirelessly in real time manner. The wired signals can be sampled by adaptors include analog input (4-20mA, 1-5V, 0-5V) signals, thermal couple signals, digital input signals, digital output signals etc. The signals type can be combined flexibly. Wireless multi-function combined adaptors are mainly used for valve position, temperature, mirror position measurement as well as non-critical motor driven valves, pneumatic valves, solenoid valves and heliostat driving motors control in CSP power plant.5) Wireless HART adaptor: sample the wired HART signals and transmit them wirelessly in real time manner. Wireless HART adaptors are used for transmitters, valve actuators and heliostats controllers with HART interface in CSP power plant.6) Wireless Modbus TCP/RTU adaptor: sample the wired Modbus TCP/RTU signals and transmit them wirelessly in real time manner. Wireless Modbus TCP/RTU adaptors are used for heliostats controllers and meteorological station with Modbus TCP/RTU interface in CSP power plant.7) Wireless valve position transmitters: Wireless valve position transmitters are mainly used for valve position sample of manual valves, motor driven valves, pneumatic valves, safety valves in CSP power plant.8) Wireless multi-function node: support construction of wireless backbone network, and support Wi-Fi equipment, wireless Ethernet equipment, and ISA-100.11a wireless transmitters’ connection.Wireless multi-function node can serve as wireless gateway.Wireless multi-function nodes are used for wireless control network and connection with wired control system of steam turbine generators in CSP power plant.9) Wireless handheld equipment: carry out wireless and wired field equipment software update, authorization, diagnosis and configuration through Wi-Fi, Bluetooth or other wireless technique.A CKNOWLEDGMENTThis paper is funded by the POWERCHINA science & technology research project: HD2013-04 Key CSP power generation technology research project.C ORRESPONDING A UTHORLi Caiyong,Email:***************,Mobilephone:133****2372R EFERENCES[1] GENGYUN WANG: Comparison and Evaluation of IndustrialWireless Sensor Network Standards ISA100.11a and WirelessHART, Master of Science Thesis, CHALMERS UNIVERSITY OF TECHNOLOGY, Gothenburg, Sweden, 2011 [2] LIU Zu-ping: An innovative theory of tracking and focusing –Chen’ssubstantial innovation in solar energy utilization research, Journal ofuniversity of science and technology of China, Vol 36, No. 12, Dec,2006。

936168-001 1 Liquid-Filled Heat Sink 替换说明书

Liquid-Filled Heat Sink Replacement InstructionsBefore you beginObserve the following requirements before removing and replacing the heat sink.WARNING : To reduce the risk of serious injury ordamage to the equipment, do not open the chassis cover of any unit with a 750W power supply. To determine if you have a 300W, 500W or 750W power supply, refer to the label on the rear of the computer.CAUTION : Never open the cover with the power cord attached or power applied. You might damage your computer or be injured by the spinning fan blades. CAUTION : Avoid touching sharp edges inside the computer.NOTICE : Static electricity can damage the electronic components inside the computer. Discharge static electricity by touching the metal cage of the computer before touching any internal parts or electronic components.Tools neededPhillips #2 screwdriverSmall screws are easily lost. Remove screws over a surface that enables you to retrieve them if they fall. NOTE : Computer appearance and features may vary by model.Removing the liquid-filled heat sink1. Press the power button to turn off the computer.2. Disconnect the power cord and all attached cables from the back of the computer.936168-0013. To remove the access panel: Slide the release latch (1), and then slide the panel back and pull it away from the computer (2).4. Locate the liquid-filled heat sink: 1. Memory modules 2. Liquid-filled heat sink3. Graphics cards5. On the outside, rear of the computer, remove the four screws that secure the fan (1). On the inside of the computer, loosen the four screws on the heat sink (2), disconnect the fan cable from the system board (3), and then lift the heat sink assembly from the computer (4).6. Touch the replacement heat sink bag to the metal of the computer, and then remove the replacement heat sink from the bag.Replacing the liquid-filled heat sink1.Insert the assembly into the computer with the heat sinkon top of the processor and the fan against thecomputer back wall (1). Tighten the four screws on theheat sink (2), and then connect the fan cable to thesystem board (3). On the outside, rear of the computer,replace the four screws to secure the fan (4).2.Position the access panel back into place on the sideof the computer (1), and then slide the release latch tothe locked position (2).3.Plug the power cord and any additional cables into theback of the computer.4.Press the power button to turn on the computer.© Copyright 2017 HP Development Company, L.P.The information contained herein is subject to change without notice. The only warranties forHP products and services are set forth in the express warranty statements accompanying suchproducts and services. Nothing herein should be construed as constituting an additional warranty.HP shall not be liable for technical or editorial errors or omissions contained herein.First Edition: April 2017PRINTER: Replace this bo x with Pr inted- In (PI)。

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A loop-heat-pipe heat sink with parallel condensers for high-power integrated LED chipsJi Li a,*,Feng Lin b,Daming Wang b,Wenkai Tian ba Laboratory of Advanced Thermal Management Technologies,College of Physics,University of Chinese Academy of Sciences,19A Yu-quan-lu Road, Shijingshan District,Beijing100049,PR Chinab College of Physics,University of Chinese Academy of Sciences,19A Yu-quan-lu Road,Shijingshan District,Beijing100049,PR Chinah i g h l i g h t sA unique loop heat pipe with parallel condensers is proposed and tested.The mechanism behind the loop heat pipe is analyzed theoretically.A general multi-purpose conﬁguration of LED illumination device is proposed.The junction temperature of the LED device can be maintained below85 C.a r t i c l e i n f oArticle history:Received28August2012 Accepted5March2013 Available online23March2013Keywords:LED coolingLoop heat pipeParallel condensersthermal resistance a b s t r a c tIn this paper,a systematic experimental study was carried out on a copper e water loop heat pipe(LHP) with dual parallel condensers,especially for high power LED illumination applications.The main high-lights of this work include:(1)a general multi-purpose conﬁguration of LED illumination device is proposed with replaceable optical lens;(2)a unique loop heat pipe with parallel condensers is proposed and tested for theﬁrst time.From the experimental measurements,at low heat loads,it is observed that the uneven-distribution of workingﬂuid into different condensers exists;with increase of the heating loads,this uneven-distribution will disappear.Meanwhile,the obtained results from the experiments and the theoretical analysis show that different operation modes will result in different heat transfer performance of the loop heat pipe.For the present design,the loop heat pipe heat sink has a total thermal resistance ranging from1.0to0.4 C/W(heating loads ranging from30W to300W)from the heating source to the ambient under natural convection situation.If implementing this LHP heat sink into the proposed LED illumination package,the measured thermal performance is superior to any conventional passive thermal management solutions in term of heat sink weight at the same temper-ature control level.Ó2013Elsevier Ltd.All rights reserved.1.IntroductionIn super computers,avionic/telecommunication equipments, and photoelectric devices,the demanding for dissipation of large amount waste heat continues with the development of technolo-gies.A proper thermal management solution is critical to the operation of these equipments,regarding the safety,reliability and life term issues[1].Light emitting diode(LED)as a solid state semiconductor device,which is becoming dominant in domestic and commercial lighting technologies,also faces the same problem.Presently,even though LED has a fairly satisfactory progress in the photoelectric conversion efﬁciency,more than eighty percent of the electric power adding to LED devices still changes to waste heat. Like other electronic devices,the maximum junction temperature of LED chips should be cooled at a suitable temperature(normally below150 C)to keep its photoelectric conversion efﬁciency during all the operating life.If there is no proper thermal management,for a100W integrated Chip-on-Board(COB)LED chip as shown in Fig.1,its temperature will rise to several thousand degree Celsius. The traditional types of heat sinks to cool LEDs mainly include:(1) metalﬁn heat sinks;(2)heat pipe integrated assemblies.Till now, metalﬁn heat sinks are still the main thermal management solu-tions for LEDs,however,the heat pipe integrated assemblies (including heat pipe,vapor chamber,and thermal tower,etc.)are*Corresponding author.Tel.:þ8613522278866.E-mail address:jili@(J.Li).Contents lists available at SciVerse ScienceDirectApplied Thermal Engineeringjournal ho mep age:www.elsevi/locate/apthermeng1359-4311/$e see front matterÓ2013Elsevier Ltd.All rights reserved./10.1016/j.applthermaleng.2013.03.016Applied Thermal Engineering56(2013)18e26attracting more and more attention.With the increasing trend of the packaging density and the LED power consumption,the asso-ciated heat ﬂux from a LED chip increases dramatically,even some scholars proposed to use active cooling methods to cool LEDs,including liquid cooling [2,3].The drawbacks by using active cooling are obvious:once the fan or pump used to circulate the cooling ﬂuid is broken down,the whole lighting apparatus will burn out due to the insuf ﬁcient heat removal channels,especially when facing the unpredictable and severe working conditions for outdoor use.Among the traditional cooling technologies,metal ﬁn heat sinks have the highest reliability,but for the integrated high power LEDs array as shown in Fig.1,the metal ﬁn heat sink with natural con-vection cannot bear the heating load (the thermal resistance of metal ﬁn heat sinks cannot easily meet the requirement for high heat ﬂux applications).For latest technologies in the market,the apparent heat ﬂux of LEDs array,q apparent ¼Q power /A array ,is larger than 15e 20W/cm 2,and furthermore the whole illumination sys-tem will become too heavy.Heat pipe integrated assemblies have good potential in solving the problem,but the designed heat pipe heat sink is either complicated,or dif ﬁcult to implement,or paratively speaking,a loop heat pipe has its unique merits superior to other all conventional solutions as mentioned above for high power LED applications.A loop heat pipe is a passive two-phase heat transfer device with different working characteristics compared to a conventional heat pipe.The basic structure and the fundamental principle for a loop heat pipe can be found in the literature [4,5].Some of the advan-tages of implementing a loop heat pipe in electronic cooling are summarized by Maydanik et al.[4,5]as:(i)a much higher capacity at comparable dimensions;(ii)ef ﬁcient operation at any orienta-tion in the gravity ﬁeld;(iii)a lower thermal resistance;(iv)ﬂexi-bility in packaging;(v)high heat transfer loads over considerable distance and so on.The ﬁrst loop heat pipe (LHP)was invented in the former Soviet Union in 1974and was patented in 1985[5].Previously,most of the applications for LHPs can be found in aerospace engineering.However,with the development of infor-mation technologies,loop heat pipes are attracting extensive attention for electronics thermal management [4].As indicated by Maydanik [4],the increased heat dissipation requirement in different electronics cooling situations and the efforts in LHP miniaturization make it possible to implement LHPs as a promising means in the thermal management of high power electronics.Historically,inverted con ﬁgurations of the evaporator and the small distance between the compensation chamber and the evap-orator seldom selected high thermal conductivity wick material,e.g.,copper,in conventional loop heat pipes.Nickel or titanium is the common wick and casing material with a cylindered type of evaporator for a typical loop heat pipe design.However,the cost and the dif ﬁculties in manufacturing with the above mentioned materials will limit the implementation of loop heat pipes incommercialized electronic/photoelectric products.There were few publications on the topic of usage of loop heat pipe in LEDs cooling [6],and in the market,it is rare to see other types of loop heat pipe evaporators than a cylindered type.Meanwhile,a loop heat pipe with COMPLETE parallel con-densers cannot be found in the historic publications [7e 9].Dus-singer et al.[7]developed an aluminum/ammonia loop heat pipe thermal control system with parallel condensers for micro satellite to transport 700W of heat and in aid to enhance the ﬂow stability,a ﬂow balancer was designed and installed.Koveal [8]developed a plate type loop heat pipe with dual parallel plate type condensers by using MEMS fabrication methods to achieve a low thermal resistance of 0.05 C/W.All the above mentioned works adopted similar con ﬁguration,in which the parallel condensers shared a vapor line and a liquid line connected to the main evaporator even though their size and shape were totally different.Actually,this kind of con ﬁguration is a quasi-parallel type and will cause a serious issue:the working ﬂuid will interact with each other when ﬂowing into condensers and out of condensers,which will result in unexpected mixing of working ﬂuids before they return back to the evaporator and most worse,this kind of interaction may cause partial de-priming of the evaporator or sudden over-shoot in the evaporator temperature [7e 9].In general speaking,loop heat pipe is a very promising tool to manage high power density heat.But,the traditional design has some drawbacks when implementing a loop heat pipe in the electronic cooling,e.g.,the interference of connecting lines to the evaporator or condenser,or operation instability,or too compli-cated system.Li and his co-workers had proposed a unique square ﬂat LHP evaporator with wicked ﬁns directly sintered on the sub-strate (or casing)of the LHP evaporator [10,11],in which the vapor removal channels are located in the wick in contrast to the con-ventional grooved vapor channels in the substrate,and the compensation chamber is formed directly in the evaporator and separated from the vapor side by the unique wick structure,as shown in Fig.2.With this novel design of the porous structure,an extremely low thermal resistance in the LHP evaporator has been obtained.Moreover,this unique type of evaporator has agreatFig.1.An integrated 100W COB LEDchip.Fig.2.A unique square ﬂat LHP evaporator with wicked channels [10,11].J.Li et al./Applied Thermal Engineering 56(2013)18e 2619compatibility with different kind of con ﬁgurations of vapor lines and liquid lines,even for complete parallel condensers structure.In this research,a novel loop heat pipe with dual complete parallel condensers is developed for high power integrated LED chip cool-ing based on the unique evaporator structure proposed by Li et al.[10,11].The vapor lines and liquid lines from the condensers are all connected to the evaporator directly.This kind of con ﬁguration will overcome the drawbacks reported in the previous works related to the quasi-parallel condensers,which is veri ﬁed by thorough ex-periments as presented in the following sections.At the same time,the mechanism for a loop heat pipe with complete parallel con-densers is discussed based on the experimental observations and is analyzed theoretically.2.Fabrication of loop heat pipeA loop heat pipe with parallel condensers has many advantages in theory compared to one with single condenser:(1)higher heat transfer capacity even if the total heat transfer area for both are same;(2)lower thermal resistance due to reduction in ﬂow resis-tance along the loops;(3)symmetric design to comply with special required arrangement;(4)more ﬂexible and reliable in gravity environment.Firstly,a multipurpose LED illumination device is proposed here,as shown in Fig.3,which could be used for different lighting ap-plications with replaceable optical lens and external guard shields,e.g.,for ﬂood lighting,street lighting,or warehouse lighting.The present loop heat pipe for the LED system is shown in Fig.4.It has a rectangle plate evaporator with a dimension of 30mm (L)Â30mm (W)Â15mm (H),two vapor lines and two liquid lines,and dual parallel condensers.The inner diameter of the connecting lines is 5mm.The dimension of either condenser is 120mm Â80mm Â50mm.The total weight of the loop heat pipe heat sink is slightly less than 600g.The working ﬂuid is water,which is the most environmental-friendly liquid and has a highest merit number among all low operation temperature working liq-uids.The working ﬂuid will evaporate in the wick structure inside the evaporator,and then ﬂow automatically to the condensers due to the pressure difference between the evaporator and the ter the condensed water is driven by capillary force provided by the menisci inside the evaporator wick and ﬂow back to the compensation chamber to re ﬁll the wick continually to accomplish the circulation.The casing and the wick are made of pure copper.The mean pore size is about 65microns with a porosity of about 50%and the wick permeability is around 6Â10À11m 2.The charging amount of water is calculated from the total volume of the porosity of the wick,the compensation chamberand one of two full loops,which guarantees that at least one of parallel loops would never dry out under any circumstances.It should be noted that due to some unpredictable situations for pressure distribution inside the loop heat pipe,the uneven-distribution of working ﬂuid in each loop does exist.As the consequence,it may happen that the liquid will accumulate in one loop and another loop will be partially short of working ﬂuid.This phenomenon takes place more frequently at low heating loads or low cooling source temperature (here it is the atmospheric tem-perature).At this situation,the liquid-ﬁlled loop will act as a big extra compensation chamber,and only another side will work normally to deliver heat from the evaporator to the working condenser with reduced heat dissipation ef ﬁciency.Furthermore,the design of the condensers for the present purpose also plays an important role in the heat transfer ef ﬁciency at the system level.The pitch of the ﬁns around the serpentine pipelines has been numerically studied with commercial software to obtain a possible optimum performance.For ease manufacturing,straight plate ﬁns were adopted here.However,if a lower system thermal resistance is wanted,there still exist rooms to further improve the heat transfer performance of the condensers.The actual prototype of the tested loop heat pipe is illustrated in Fig.3,in which the condensers were arranged above the evaporator to make use of gravity to aid in increasing the ﬂow rate and reducing the thermal resistance.3.Experimental system and theoretical analysisThe dimension of the evaporator is 30mm (L)Â30mm (W)Â15mm (H).The dimension of either condenser is 120mm (L)Â80mm (W)Â50mm (H).The inner diameter of the vapor line and liquid line is 5mm.The test section and the places where the thermocouples were located are illustrated in Fig.5.Thirteen microscale T-type Omega thermocouples were ﬁrmly attached onto the loop heat pipe by ﬁlm adhesive to measure the following temperatures:the temperature at the top surface of the heating block (#101);the temperature at the top surface of the compensation chamber (#102),the temper-ature at the exits of the evaporator (#103and #203),the temper-ature at the entrance of the condensers (#104and #204),the temperature at the middle point of the serpentine tubes of the condensers (#105and #205),the temperature at the exit of the condensers (#106and #206),the temperature at the entrances of the evaporator (#107and #207)respectively.It should be noted that a double-check procedure has been performed by detecting the electro-conductance between the thermocouples and the loop heat pipe to guarantee the effective attachment and avoid any possible failure or error in the measurements.The tested loop heat pipe sample was fastened onto a heating copper block with a square surface (active heating area)of 25mm Â25mm for imitating a commercial integrated COB LEDs array chip with a typical size of one inch by one inch.Five commercial cylindrical cartridge heaters were soldered in the copper block,which can provide a heating power from 0to 628W maximum.Two micro-scale T-type Omega thermocouples were inserted in the copper block by soldering,to monitor the heating power.There was a very thin layer of thermal grease used to ﬁll the possible air gap between the copper heating block and the loop heat pipe (the thermal conductivity of the grease used in the test is 3.86W/m K and the thickness of the grease is typically less than 0.02mm with a stan-dard clip ﬁxture).There was another thermal couple (#108)for measuring the ambient temperature.The experimental system was explained in detail in other places [10,11].The experimental setup includes an infrared camera,a data acquisition unit,a DC power supplier and the test section.A DC power supplier is used to provide heating power to thecartridgeFig.3.A multi-purpose LED illumination apparatus and the fabricated prototype of the tested article.J.Li et al./Applied Thermal Engineering 56(2013)18e 2620heaters.The data acquisition unit includes an Agilent data acqui-sition unit and a computer to monitor and record the temperatures from the thirteen thermocouples.The infrared camera is used for the monitoring of the temperature distribution in the loop heat pipe under different heating loads.The following equation is widely used to calculate the total thermal resistance from the heating source to the ambient:R total¼T case ÀT a Q(1)Here Q is the heat load which was calculated directly from the electric power added to the cartridge heaters;T case is the measured temperature at the central point of the top surface of the copper block (thermocouple #101,which was ﬁxed in the grooved surface using thermally conductive epoxy glue);T a is the ambient tem-perature (thermocouple #108).Eq.(1)takes into account the thermal resistances added by the thermal interface material (thermal grease here)and from the convective heat transfer from the condenser to the environment.The infrared camera has an inaccuracy of Æ2.0 C.The standard measurement error of the thermocouples is about Æ1.0 C from the datasheet of the products (or Æ0.75%).The main uncertainty in the experiments is the heat loss to the environment from the copper block,even covered by the thermal insulation materials peripher-ally,and was determined by the heat conduction in the copper block as less than 5%in the calculation of the heat load Q subjected to the loop heat pipe.Thus,from the error propagation,the maximum uncertainty in the thermal resistance calculations will be less than Æ6.5%.In order to explore the operation mechanism for a loop heat pipe with dual parallel condensers,a theoretical model is devel-oped here based on previous works [12,13].For a loop heat pipe with one condenser,given a certain heat load Q ,the mass ﬂow rate of liquid in a loop heat pipe is,_m¼Qfg(2)For a loop heat pipe with dual parallel condensers,if only one condenser works normally as mentioned previously,the above equation still works;if both condensers involve in the operation,the mass ﬂow rate for liquid in the each loop will be,_m0¼Q2h fg(3)Also the same calculation will also be applied for vapor phase.It is well known that the pressure losses in one loop should be balanced by the capillary force to keep the continuous operation of the loop heat pipe,D P cap ¼D P v þD P l þD P w H D P g(4)The pressure loss for the vapor phase in one loop can be calculated fromD P v ¼XiD P i ¼D P v c þD P v l þD P v ;condenser(5)The terms in the right hand of the above equation take into account the pressure drop in the vapor removal channels (rectan-gular shape)in the wick D P vc ,in the vapor line (circular pipe)D P vl ,and in the vapor section of the condenser (circular pipe)D P v ,con-denser respectively.All the above parameters can be calculated from the theoretical analysis as developed by Li and Peterson [13]with a detailed thermodynamic analysis.Some important steps will be repeated here for the completeness and legibility.In the vapor removal channel,D P v c ¼2u v c $g $m v $l v cd v c(6)where,u v c ¼ð_m=n v c $H $W $r v Þ,g ¼4.7þ19.641þ(a 2/(1þa )2,and a ¼H /W .In the vapor line,D P v l ¼128$l v l $y v $_m$d v l(7)And in the vapor section of the condenser,D P v ;condenser ¼128$l v ;c $y v $_m p $d c(8)For the pressure loss of the liquid phase in one loop,D P l ¼P l ;c ÀP l ;cc ¼128$l ll $y l $_m p $d 4ll(9).Here it is assumed that the liquid only ﬁlls in the liquid return line for a ﬁrst-order estimation and convenience.However,this kind of assumption is fairly far from the real situation,especially for a loop heat pipe with two parallel condensers.For the pressure loss in the wick during liquid ﬂow,D P w ¼P l ;cc ÀP l ;w ¼m l $u l ;w $d wPDarcy Equation (10)where,u l ;w ¼ð_m=r l $A w Þ,and K p is thepermeability.Fig.4.An illustration of a loop heat pipe with dual complete parallel condensers for LED cooling.yout of the test section and the thermocouples arrangement.J.Li et al./Applied Thermal Engineering 56(2013)18e 2621And ﬁnally,from the gravity,D P g ¼ðr l Àr v Þgh(11)Thus,all of the terms in Eq.(4)can be ﬁxed theoretically.For a loop heat pipe with a single loop [12],the evaporator temperature under a certain heat load Q is,T v ;e ¼T a þ1a c ;ext S c ;ext þR wall þ1a c ;int S c ;intþX iD P i $d T d P T þ1a e S e ;active!$Q (12)For a loop heat pipe with dual parallel condensers,through careful deduction,the evaporator temperature under a certain heat load Q is developed herein,T v ;e¼T a þ 1a c ;ext c ;ext þR wall þ1a c ;int c ;int!,2þX iD P ’i $d T d P T þ1a e S e ;active !$Q (13)Here,a c ,ext is the convective heat transfer coef ﬁcient at the externalsurface of the condenser and S c ,ext is the total heat transfer surface area of the ﬁns in each condenser;a c ,int is the heat transfer coef-ﬁcient during the vapor condensation in the condenser serpentine pipe and S c ,int is the inner surface area of the condenser pipe;R wall is the thermal resistance of the condenser pipe wall,R wall ¼d wall /(k wall $S wall ),which could be neglected due to the high thermal conductivity of copper and the thin thickness of the tube wall;a e is the equivalent evaporation heat transfer coef ﬁcient in the evapo-rator and S e ,active is the evaporator surface area to which heat Q issupplied (active area);Pi D P i is the total pressure drop of vapor during the motion of vapor from the evaporator into the workingone of the two condensers and given by Eqs.(2)and (5);Pi D P ’i is the total pressure drop of vapor when the two condensers are all in operation and given by Eqs.(3)and (5);The derivative d T =d P j is a thermophysical characteristic of the working ﬂuid which is taken along the liquid e vapor saturation line and can be calculated from the Clausius e Claperon equation approximately at a reference temperature.It should be noted that a c ,ext ,a c ,int and a e are very dif ﬁcult to calculate accurately from any theoretical correlations and more realistically these coef ﬁcients should be identi ﬁed by careful experiments.From the previous works [10,11],all of these coef ﬁcients were identi ﬁed for the two phase ﬂow heat transfer inside a loop heat pipe as a c ,int ¼ 3.0Â103W/m 2K and a e ¼5.0Â104W/m 2K respectively at a moderate heating loading,and the external natural convective heat transfer coef ﬁcient was set as a c ,ext ¼5W/m 2K,which will be substituted into Eqs.(12)and (13).For the present design,the external ﬁn area of each condenser is S c ,ext ¼0.16m 2,the inner surface area of each condenser is about S c ,int z 4.4Â10À3m 2,and the active area of the evaporator is S e ,active ¼6.25Â10À4m 2.Other properties of mate-rials are chosen directly from the published data in textbooks.From the above theoretical analysis and in order to compare with the experimental results,a theoretical prediction model for the total thermal resistance from the heating source to the ambient is established as,R total ¼T v ;e ÀT aþd TIM e ;active l TIM(14)With all the determined parameters from the previous measure-ments,from Eqs.(1)and (14),the comparison between theexperiments and the theoretical calculations can be carried out at the system level.4.Results and discussionIn the present experiments,horizontal (the condensers were located at the same level of the evaporator)and vertical arrange-ment (the condensers were located above the evaporator)were all tested.From the experiments,the gravity does have an impact on the thermal performance of the present loop heat pipe,but not signi ﬁcant.The performance variations along with the title angle will be presented somewhere else.Here only the gravity favored results are shown.Fig.6shows the startup process with a 32W input power.The present LHP exhibits temperature oscillations even after it ap-proaches quasi-steady state at low heat loads.This kind of tem-perature oscillation can also be observed for a loop heat pipe with one condenser.Some possible reasons for this oscillation at low heating loads for a loop heat pipe with a single loop were sum-marized by Li et al.[11],including:(1)the draining effect of the porous wick presented in the condenser at low heat loads.As the vapor is condensed and the liquid is drained back to the compen-sation chamber by the wick structure,some ﬂow oscillations occur;(2)at low heat loads,the vaporization process and the ﬂooding in the porous wick will take place alternatively since the low heating power cannot maintain a stable meniscus in the wick.This phe-nomenon is believed to be aggravated if the sub-cooling degree of returning liquid is increased.For a loop heat pipe with dual parallel condensers as proposed in the present study,there exhibits another new instability:at low heat loads,two condensers with a sym-metrical con ﬁguration do not operate uniformly.From Fig.6,it can be found that the inlet temperatures for each condenser have a difference of about 5 C,and the central temperatures of two condenser have a quite large difference,which is up to 15 C.From this temperature difference,it can be conferred that one of the two condensers (#2as indicated in Fig.3)did not come to a status of full operation,even the working ﬂuid circulation might turn off inside this condenser since the measured condenser temperature was just slightly larger than the room temperature.When the heating power was incremented beyond a point,which was not identi ﬁed accurately in this work,a stable vapor-ization process in the evaporator and a stable condensation process in the condensers were established,and the operation process became more stable.Figs.7e 9illustrate the temperature evolutions at different places for loop heat pipe startup tests under heat loads of 50W,100W and 300W respectively.It is clearly shown that a very stable operation mode has been achieved at a comparatively high heat load with small ﬂuctuations in the temperature.TheFig.6.The startup process and the temperature evaluation of the loop heat pipe with a32W input power.J.Li et al./Applied Thermal Engineering 56(2013)18e 2622stable operation mode is established due to the increased pressure difference between the vapor pressure in the vapor removal channels and the vapor pressure in the condensers with the in-crease of the heating power.This increase of pressure difference will eliminate the degree of the uneven-distribution of working ﬂuid and the degree of ﬂow instability in the loop.From Figs.8and 9,the temperature measurements at different places on each condenser show that the performance of the parallel condensers is very close to each other.Infrared measurements of the temperature distribution of the loop heat pipe were recorded after the loop heat pipe was approaching to its steady status and one of them is given in Fig.10for Q ¼32W (the emissivity of the copper was set as 0.97here).From Fig.10,the measured temperatures of heating block surface and the evaporator agree with the measurements from the ther-mocouples quite well as presented in Fig.6.Through the IR camera,the non-uniformity of temperature distribution in each condenser at low heat loads is revealed more clearly and one of the condensers did not work normally (the left one in Fig.10).For a high heat load,e.g.,Q ¼100W,one of infrared measurements of the temperature distribution of the loop heat pipe is shown in Fig.11.From Fig.11,the temperature distribution in each condenser at high heat loads is almost the same and the parallel condensers all work normally.From the de ﬁnition of the total thermal resistance as given in Eq.(1)and using a time averaged calculation,Fig.12gives the heat load dependence of the total thermal resistances for the whole device from the experiments (the solid lines with marks)for heat loads ranging from 30W to 300W.And in Fig.12,the theoretical results for 30W with single condenser and 100W with dual condensers (the dot lines)are illustrated for a simple comparison.For the present con ﬁguration and under natural convection,the totalthermal resistance is as low as 0.6 C/W for a 100W heating load from experiments,which is very close to the theoretical value of 0.69 C/W from Eqs.(13)and (14)with all the parameters given in the context.But,for a low heat load of about 30W,the total thermal resistance is located between 0.95 C/W (when two condensers were all in operation)and 1.41 C/W (when just one condenser was in operation).For single loop operation under a 30W heating load,from the theoretical calculation with Eqs.(12)and (14),the total thermal resistance is 1.37 C/W,which agrees with the experi-mental result with an acceptable discrepancy if considering the measurements error and the limitation of the theory.Since the theoretical analysis as shown in this work assumed a constant heat transfer mode (all parameters are kept as constant)for a loop heat pipe,this simpli ﬁcation causes the discrepancy between the theoretical calculation and the experimental results.Due to unpredictable reasons,sometimes one of the parallel condensers could stop working,the ﬂow resistance and pressure drop in another condenser will increase since all the ﬂuid will circulate in one loop,consequently the thermal resistance will in-crease.What causes one condenser stop working is still unclear and need more visualization experiments.It is speculated that at the low heat loads,the two-phase ﬂow in each loop is fairly unstable and the velocity of the working ﬂuid is quite low.When vapor phase condensed totally in either of the condensers and if the pressure difference between the evaporator and the condenser cannot overcome the ﬂow resistance,this side will be blocked by the condensed liquid and be out of work.This instability may be ampli ﬁed if the external cooling temperature is quite low.When the heating load is increased beyond 50W for the present design,this phenomenon of non-symmetric operation will disappearandFig.7.The startup process and the temperature evaluation of the loop heat pipe with a 50W inputpower.Fig.8.The startup process and the temperature evaluation of the loop heat pipe with a 100W inputpower.Fig.9.The startup process and the temperature evaluation of the loop heat pipe with a 300W inputpower.Fig.10.Infrared temperature measurements of the loop heat pipe at 32W.J.Li et al./Applied Thermal Engineering 56(2013)18e 2623。