Chapter2 Properties of Fluid(3)

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Hydraulic LibraryRev 9 - November 2009Copyright © LMS IMAGINE S.A. 1995-2009AMESim® is the registered trademark of LMS IMAGINE S.A.AMESet® is the registered trademark of LMS IMAGINE S.A.AMERun® is the registered trademark of LMS IMAGINE S.A.AMECustom® is the registered trademark of LMS IMAGINE S.A.LMS b is a registered trademark of LMS International N.V.LMS b Motion is a registered trademark of LMS International N.V.ADAMS® is a registered United States trademark of MSC.Software Corporation. MATLAB and SIMULINK are registered trademarks of the Math Works, Inc. Modelica is a registered trademark of the Modelica Association.UNIX is a registered trademark in the United States and other countries exclusively licensed by X / Open Company Ltd.Python is a registered trademark of the Python Software Foundation.Windows and Visual C++ are registered trademarks of the Microsoft Corporation. The GNU Compiler Collection (GCC) is a product of the Free Software Foundation. See the GNU General Public License terms and conditions for copying, distribution and modification in the license file.All other product names are trademarks or registered trademarks of their respective companies.Hydraulic Library Rev 9 Table of contentsChapter 1:Tutorial examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11.1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2Example 1: A simple hydraulic system . . . . . . . . . . . . . . . . . . . . . . 2Cavitation and air release. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.3Example 2: Using more complex hydraulic properties . . . . . . . . . 11Using one of the special fluids . . . . . . . . . . . . . . . . . . . . . . . . . . 121.4Example 3: Using more complex line submodels . . . . . . . . . . . . . 171.5Example 4: Valves with duty cycles. . . . . . . . . . . . . . . . . . . . . . . . 221.6Example 5: Position control for a hydraulic actuator. . . . . . . . . . . 271.7Example 6: Simple design exercise for a hydraulic suspension . . 33Chapter 2:Theory of fluid properties. . . . . . . . . . . . . . . . . . . . . .412.1Density and compressibility coefficient . . . . . . . . . . . . . . . . . . . . . 41Entrapped air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Dissolved air. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432.2Air release and cavitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442.3Viscosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Viscosity influence on the flow. . . . . . . . . . . . . . . . . . . . . . . . . . 48Flow through orifices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49Frictional drag. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Chapter 3:AMESim Fluid Properties . . . . . . . . . . . . . . . . . . . . . .553.1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55FP04. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553.2Tutorial example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Chapter 4:Hydraulic Line modeling. . . . . . . . . . . . . . . . . . . . . . .614.1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61Zero-dimensional line submodels. . . . . . . . . . . . . . . . . . . . . . . . 61“Lumped” and “Lumped distributive” line submodels. . . . . . . . . 62Lax-Wendroff “CFD 1D3” line models . . . . . . . . . . . . . . . . . . . . 63Choosing between Lumped/Distributive and CFD 1D Lax-Wendroffmodels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644.2Line submodel selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 641Table of contents24.3Three important quantities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65Aspect ratio. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65Dissipation number. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66Communication interval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67 4.4The selection process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68Hydraulic Library Rev 9 Chapter 1: Tutorial examples1.1IntroductionThe AMESim Hydraulic library consists of:• A collection of commonly used hydraulic components such as pumps, motors, orifices, etc. including special valves.•Submodels of pipes and hoses.•Sources of pressure and flow rate.•Sensors of pressure and flow rate.• A collection of fluid properties.Hydraulic systems in isolation serve no purpose. It is necessary to do somethingwith the fluid and also to control the process. This means that the library must becompatible with other AMESim libraries. The following libraries are frequently usedwith the Hydraulic library:Mechanical libraryUsed in fluid power application when hydraulic power is translated into mechanicalpower.Signal, Control and Observer libraryUsed to control the hydraulic system.Hydraulic component design libraryUsed to build specialist components from very basic hydraulic and mechanicalelements.Hydraulic resistance libraryThis is a collection of submodels of bends, tee-junctions, elbows etc. It is usedtypically in low pressure applications such as cooling and lubrication systems.1Chapter 1Tutorial examples2Chapter 1 of the manual consists of a collection of tutorial examples. We strongly recommend that you do these tutorial examples. They assume you have a basic level of experience using AMESim . As an absolute minimum you should have done the examples in Chapter 3 of the AMESim manual and the first example of Chapter 5 which describes how to do a batch run.1.2Example 1: A simple hydraulic systemObjectives•Construct a very simple hydraulic system •Introduce the simplest pipe/hose submodels •Interpret the results with a special reference to air release and cavitationFigure 1.1: A very simple hydraulic system In this exercise you will construct the system shown in Figure 1.1. This is perhaps the simplest possible meaningful hydraulic system. It is built partly fromcomponents from the Hydraulic category (which are normally blue) and partly from the Mechanical category.The hydraulic section is built up from standard symbols used for hydraulic systems. The prime mover supplies power to the pump, which draws hydraulic fluid from a tank. This fluid is supplied under pressure to a hydraulic motor, which drives a rotaryNote:•You can use more than one fluid in the Hydraulic library. This is important because you can model combined cooling and lubrication systems of a library.•The hydraulic library assumes a uniform temperature throughout the system. If thermal effects are considered to be important, you should use the Thermal Hydraulic and Thermal Hydraulic Component Design libraries.•There are models of cavitation and air release in the hydrauliclibrary. Note also there is a special two-phase flow library. Atypical application for this is air conditioning systems.Hydraulic Library Rev 9load. A relief valve opens when the pressure reaches a certain value. The output from the motor and the relief valve returns to the tank. The diagram shows three tanks but it is quite likely that a single tank is employed.The first category contains general hydraulic components. The second contains special valves.The hydraulic components used in the model you will build can all be found in the first of these Hydraulic categories. If you click on this category icon, the dialog box shown in Figure 1.2 opens.First look at the components available in this library. Display the title of components by moving the pointer over the icons:Figure 1.2: The components in the first hydraulic category.Close the Library before continuing.3Chapter 1Tutorial examples4Step 1:Use File X New... to produce the following dialog box.Figure 1.3: The hydraulic starter system.Step 2:Construct the rest of the system and assignsubmodels1.Construct the systemwith the components as shown in Figure 1.1.2.Save it ashydraulic1.3.Go to Submodel mode.Notice that the drop, prime mover, node and pipes do not appear the same as they usually do. This is because they do not have sub models associated with them.The easiest way to proceed is as follows:4.Click on the Premier submodel button in the menu bar.Select the hydraulic starter circuit libhydr.amt and then click onOK. A new system with a fluid properties icon in the top leftcorner of the sketch is created.You could also have clicked on the New icon in the tool bar butif you do this you will have to add the fluid properties iconyourself.Hydraulic Library Rev 95Figure 1.4: The line submodels.You get something like Figure 1.4. It is possible that your system may have HL000associated with one of the other line runs. These minor variations are dependent on the order in which you constructed the lines. They will not influence the simulation results.An important feature to note is that a line run has a special submodel (HL000) which is not a direct connection. To emphasize this point the line run has a special appearance:Remember the submodel DIRECT does nothing at all. It is as if the ports at each end of the line were connected directly together.In contrast, HL000 computes the net flow into the pipe and uses this to determine the time derivative of pressure. If the net flow into the pipe is positive, pressure increases with time. If it is negative, it decreases with time. The pressure created by HL000 is conveyed to the relief valve inlet. The motor inlet is conveyed by the node and submodel DIRECT .5.Click the mouse right-button.6.Select Show line labels in the label menu.Chapter 1Tutorial examples6Step 3:Set parameters1.Change to Parameter mode.2.Set the following parameters and leave the others at their default values:Figure 1.5: Setting the line submodel HL000 parameters.3.To display the parameters of a line submodel click the left mouse button with thepointer on the appropriate line run.Part of the dialog box for HL000 is shown in Figure 1.5. The compressibility of the oil and the expansion of the pipe or hose with pressure are taken into ac-count together with the pipe volume. HL000 normally requires the bulk modulus of the hydraulic fluid and pipe wall thickness together with the Young’s modulus of the wall material. From these values an effective bulk modulus of the com-bined fluid and pipe walls can be calculated. The effective bulk modulus of a hose is normally very much less than that of a rigid steel pipe.4.Click on the fluid icon FP04 in the sketch.A new dialog box as shown in Figure 1.6 is displayed. This shows you the prop-erties of the hydraulic fluid. Currently they are at their default values and the ab-solute viscosity, bulk modulus, air/gas content and temperature are given in common units.Submodel Title ValueHL000pipe length [m]4RL00coefficient of viscous friction [Nm/(rev/min)]0.02Figure 1.6: Parameter for fluid properties submodel FP04.5.Click on Close .Step 4:Run a simulation1.Go toSimulation mode and do a simulation run.The default values in the Run Parametersdialog box are suitable for this exam-ple.2.Click on the Start a simulation button.3.Click on the pump component to produce the dialog box shown in Figure 1.7.Some variables such as a pressure have no direction associated with them. ANote that the first item in the list is an enumeration integerparameter. A collection of properties of varying complexityare available but for this exercise elementary is satisfacto-ry.Tutorial examples(gauge) pressure of -0.1 bar indicates that the pressure is below atmospheric.In contrast other variables, such as flow rate, do have a direction associatedwith them. A flow rate of -6 L/min indicates that the flow is in the opposite direc-tion to some agreed standard direction.Figure 1.7: The Variable List for PU001.Note that you can use the Replay facility to give you a global picture of the re-sults. Figure 1.8 also shows the flow rates in L/min at a time of 10 seconds.Figure 1.8: Flow rates displayed in replay.4.To plot a variable associated with a line submodel, click on the correspondingline run.5.Plot pressure at port 1 for HL000.Figure 1.9: The pressure in the hydraulic pipe.Notice how the pressure goes up to just over the relief valve setting (150 bar).During this time the load speeds up rapidly and actually 'over-speeds'. At thispoint the motor is demanding more hydraulic flow than the pump can supply.The result is that the pressure must drop and the relief valve closes. The pres-sure continues to drop and falls below zero bar gauge. However, pressure is notlike voltage or force. We cannot have a pressure of -100 bar. The absolute zeroof pressure is about -1.013 bar gauge. It is time to introduce two terms. Cavitation and air releaseWhen pressure falls to very low levels, two things can happen:•Air previously dissolved in the fluid begins to form air bubbles.•The pressure reaches the saturated vapor pressure of the liquid andbubbles of vapor appear.These phenomena are known respectively as air release and cavitation. They cancause serious damage. Using the Zoom facility, the graph gives a better view of thelower pressure values:Figure 1.10: Low pressure in the hydraulic pipeAll AMESim submodels have hydraulic pressure in bar gauge. The low pressureshown in Figure 1.10 : Low pressure in the hydraulic pipe is caused by the loadTutorial examplesspeed exceeding its steady state or equilibrium value. This is highly undesirablebehavior as it can result in damage to the real system.In reality the starting values we have given for the pipe pressure and load speed arenot very realistic and the prime mover would start from rest or a valve would be usedto regulate the flow to the motor. However, hydrostatic transmission systems likethis often do suffer badly from cavitation and air release problems.Note that all AMESim submodels display hydraulic volumetric flow rate in L/min.There are two possible interpretations of this flow rate:•The flow rate is measured at the local current hydraulic pressure, or•The flow rate is measured at a reference pressure.AMESim adopts the second alternative with a reference pressure of 0 bar gauge.This means that the volumetric flow rate is always directly proportional to the massflow rate. In most situations the difference between the two flow rates is negligible.However, there are three situations when there is a significant difference:1.There is a very large air content; the pressure drops below the satu-ration pressure for air in the liquid and air bubbles are formed in theliquid.2.The pressure drops to the level of the saturated vapor pressure of theliquid and cavities of vapor form.3.Extremely high variations in pressure occur such as in certain typesof fuel injection systems.The first situation is called air release and the second cavitation. If there is cavitationor significant air release at the inlet to a pump, the flow rate according to the firstdefinition will not be reduced. However, with the AMESim approach (measuringflow rate at a reference pressure) it is significantly reduced.The properties of hydraulic fluids vary a great deal. Modeling them is a veryspecialist process and the model can be extremely simple or highly complex. Therun times are greatly influenced by this level of complexity.1.3Example 2: Using more complex hydraulicpropertiesObjectives:•Use more complex models of fluid properties.•See how air content changes the performance of the system.In the Hydraulic category two special components can modify the fluid properties:This is an example of a component without ports. We cannot connect this icon to any other.There are two important points to note aboutFP04.1.It has an integer parameter index of hydraulic fluid that is in the range 0 to 100inclusive. This arrangement means that it is possible to have more than one fluidin an AMESim system.•simplest This has a constant absolute viscosity. The bulk modulus isconstant above the gas saturation pressure and is 1/1000 of this valuebelow the gas saturation pressure. This model is very old but is still usedby some AMESim users.It is likely to give the fastest runs.•elementary This is the default and features a constant liquid bulk mod-ulus with absolute viscosity. The treatment of fluid properties under airrelease and cavitation is done.•advanced This gives you access to some cavitation parameters not ac-General Hydraulic PropertiesIn AMESim always use this fluid properties icon. It is associated withone submodel: FP04. This is a collection of simple and complex fluidproperties.Drop Hydraulic PropertiesThis is a special model, only used to ensure backward compatibilitybetween 4.0 models and earlier. Do not use this model.2.The characteristics of the fluid properties are de-termined by its parameters. These are set in thetype of fluid properties list. There are 7 possi-bilities:Tutorial examplescessible in the elementary properties.•advanced using tables This is like the advanced option but you install tables of data to give variation of bulk modulus and absolute viscositywith pressure and temperature.•Robert Bosch adiabatic diesel These properties are provided by Rob-ert Bosch GmbH and comprise a number of common types of diesel fuel.•elementary with calculated viscosity•advanced with calculated viscosityUsing one of the special fluidsStep 1:Use the Advanced fluid properties.1.Return to the first example of this manual, add another fluid properties icon.e Premier submodel and go to Parameter mode. Your sketch should look likethis.Figure 1.11: The sketch with two instances of FP04.3.Look at parameters of FP04-2. Change the enumeration integer parameter toadvanced. The Change Parameters list should now look like this:Figure 1.12: The advanced fluid properties.Change the index of hydraulic fluid in FP04-2 to 1. This is a number in the range0 to 100. If you look at the other hydraulic components in the system you willfind they have index 0 and hence they will still use the fluid properties of FP04-1. We could go into every hydraulic component using this second fluid and setthe parameter index of hydraulic fluid to 1. This would be extremely tedious witha big system and there is always the possibility of missing one.Instead we can set all fluid indices to the same value of 1.Step 2:Set all fluid indices to the same value of 1The best way to do this is to use the common parameters facility.e Edit X Select all.All the system components will be selected, unselect FP04-1 by holding the SHIFT key and clicking on the component.Figure 1.13 Select componentse Settings X Common parameters.Tutorial examplesFigure 1.14 shows the Common parameters dialog box. This is a list of commonparameters for selected objects. They occur at least twice. Since there are 3 hy-draulic tanks and they all have pressures of 0 bar, this value is displayed. Thereare a number of submodels that have a parameter index of hydraulic fluid. InFP02 the index of hydraulic fluid is set to 1 whereas in other submodels its valueis 0. The value is displayed as ???. Similarly the prime mover and rotary loadboth have a parameter (strictly speaking a variable) with title shaft speed. Sincethe two values are different, ??? is displayed.Figure 1.14: Different values for common parameters3.Set the parameter index of hydraulic fluid to 1. This will change all the parame-ters in the system except FP01 (remember we used Select all and deselectedFP01).Step 3:Run a simulation and plot some variablesYou will probably find the results very much the same as in example 1.Step 4:Organize a batch run to vary the air content1.In Parameter mode use Settings X Batch parameters.2.Drag and drop the air gas content from FP04-2 to the Batch control parametersetup dialog box.3.Set up the batch parameters as in Figure 1.15 so that the air content goes from0% to 10% in steps of 2%.Figure 1.15: Setting up a batch run varying air content4.Specify a batch run in the Run parameters dialog box and initiate the run.5.Plot several graphs of the batch run to compare results with various air contents:Tools X Batch Plot .Figure 1.16: Pressure in pipe.By zooming in on the curve in regions where the pressure is below 0 bar, you will probably find some variation in the results, but not to a significant degree.6.Change the saturation pressure in FP04-2 to 400 bar.7.Repeat the batch run and update your plot.Tutorial examplesFigure 1.17: Pressure in pipe with saturation pressure 400 bar.The variation between the runs is now very pronounced. The dynamiccharacteristics of the system are completely transformed. A few words ofexplanation are necessary.Normally the air content of a hydraulic oil is well below 1%. A typical value is 0.1%.It is normally considered good practice to keep the value as low as reasonablypossible. However, in a few applications, such as lubrication oil in gearboxes, theoil and air are well mixed. In this case, 2.5% is a typical value, and up to about 10%is possible.A reasonable quantity of air, given time, will completely or partially dissolve in thehydraulic fluid. The lowest pressure at which all the air is dissolved is called thesaturation pressure. For very slow systems all the air is dissolved above thesaturation pressure and partially dissolved below this pressure. Henry’s law givesa reasonable approximation for the fraction of air that is dissolved in equilibrium.Some systems are slow enough to stay very close to this equilibrium position(Figure 1.16). Often classic fluid power systems behave like this. The originalsaturation pressure is better for the current example.However, it does take time for the air to dissolve and this time will not be availablein fast acting systems. Fuel injection systems are a good example of this. Hencewith such systems it may be appropriate to set the saturation pressure artificiallyhigh to allow for significant quantities of air to be undissolved at all pressures.1.4Example 3: Using more complex line sub-modelsObjectives:•Use more complex line submodels.•Understand the need for a variety of line submodels.•To understand the importance of setting an appropriate line submodel.The system for this example is the same as for example 2 (Figure 1.11). We will describe the modification of the system to use more complex line submodels and the experiments performed. Finally we present a little of the theory behind the submodels.Step 1:Change submodelsAll the submodels in the current system were selected automatically. We willchange some of them manually.1.Go to Submodel mode.You will now change some line submodels.Before continuing note the following points:•The corners in the pipe runs are not physical but diagrammatic.•There are three hydraulic pipes and they meet at a point which physically will be a tee-junction.•It is necessary to have a large number of hydraulic pipe submodels.•In the present system three submodels are set: DIRECT , DIRECT andHL000.Figure 1.18: The current line submodels.None of these line submodels takes friction into account. We will suppose that the relief valve is close to the node but the pump and the motor are at such distances•This tee-junction in the sketch is described as a 3-portnode and it has the submodel H3NODE1. This modelsthe junction has a common pressure with flow rates thatgive conservation of mass.Tutorial examplesfrom the node that the pressure drop along the pipes cannot be ignored. We need to select new pipe submodels that take friction into account for the pipe runs:•from the pump to the node •from the node to the motor.2.Click on the line run attached to the pump and select HL03 in the Submodel list .Figure 1.19: The hydraulic line submodels available.Why did we not choose a more complex submodel that also included inertia? We answer this question later in this exercise.3.For the line from the node to the motor, select the submodel HL01.4.For the line between the node and the relief valve, the submodel DIRECT is al-ready selected and this is exactly what we want.Step 2:Set parameters and run a simulation1.Go to Parameter mode and set parameters for HL01 and HL03 so that both pipelengths are 5 m and pipe diameters are 10 mm .This can be done one at a time. However, we can do it another way. Press the Shift key on click on the HL03 and HL01 line runs so that they are selected. Use Settings X Common parameters . Figure 1.20 shows the Commonparameters dialog box.Note the brief description of each line submodel. In these de-scriptions C stands for compressibility, R for resistance (pipefriction) and I for inertia (fluid momentum). HL000 which weused before takes into account compressibility only. HL03takes into account compressibility and friction. It is modeled liketwo hydraulic compressible volumes with a resistance betweenthem.Figure 1.20: The common parameters of the two line submodels.Note that ??? indicates that different values are set in the line submodels. Set the index of hydraulic fluid to 1, diameter of pipe to 10 and pipe length to 5.2.In FP04-2 reset the saturation pressure (for dissolved air/gas) to 0 bar.3.Run a simulation with the default run parameters. Do not forget to reset RunType to Single run if you have previously run a Batch.4.Plot the two pressures in HL03.Figure 1.21: Pressures at the ends of pipe joining pump to node.Note that there is a large pressure drop along the line. This could be regarded as a sizing problem but in addition it would be bad practice to site the relief valve so far from the high pressure point.Tutorial examplesStep 3:We now investigate other line submodels.1.Return to Sketch mode and Copy-Paste part of the system as shown:Figure 1.22: Part of the system is duplicated.2.In Submodel mode change the lower two line submodels as follows:Figure 1.23: New line submodels.This system will enable you to make direct comparisons between results.3.Go to Run mode and do a simulation. Plot the pressure at the pump outlet (pres-sure at port 2).Figure 1.24: Pressure at pump outlet.We note that the curves are virtually the same. (Try zooming.) There is abso-lutely no advantage to using HL07 and HL09 instead of HL01 and HL03. If we separated the two systems and ran them independently we would find run times for the more complex submodels were higher.4.C hange the communication interval in the Run Parameters dialog box to 0.001sand rerun the simulation.If you have a look at the Warnings/Errors tab of the Simulation run dialog box, you will find that some checks are performed by the line submodels (see Figure1.25). A similar message is issued for HL03.Figure 1.25: Messages under the Warning tab.It is suggested that:•HL01 should be replaced by HL07 and•HL03 should be replaced by HL09.In other words with this communication interval the lower subsystem is better than the upper. If you replot the pressures at the pump outlets, there are clearly differences. This is what happens if you zoom.Figure 1.26: Zoomed pressures at pump outlet.The violent (and unrealistic) start up has created this oscillation in the pressure of about 56 Hz. It is damped out by 0.1 seconds. Why did we get no warning message in the previous run? The answer is that a lot of checks are applied to your submodel choices when the run starts. These take into account the fluid properties, the pipe dimensions and the communication interval.。

Chapter 2 Propertities of Fluids

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Fluid Mechanics
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Fluid Mechanics
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4 Viscosity
The viscosity of a fluid is a measureof its resistance to shear or angular deformation, and it is an inherent property of the fluid.
real fluid 0 ideal fluid 0

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types of fluid
Fluid Mechanics
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5 Surface Tension of Liquids
Liquids have cohesion and adhesion, both of which are forms of molecular attraction. Cohesion enables a liquid to resist tensile stress, while adhesion enables it to adhere to another body.
modulus of compression
Fluid Mechanics
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2 Compressibility and Expandability of Liquids
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溶液稀释英文版的教学课件 CHAPTER 2

2.3 Boiling-point Elevation and Freezing-point Depression
2.3.1 Boiling-point Elevation
2.3.1.1 Normal boiling point
The normal boiling point of a liquid is the temperature at which its vapor pressure equals 101.3 kPa(1 atm).
The boiling-point elevation, ΔTb, is found to be proportional to the molality, bB , of the solution (for dilute solution).
ΔTb = Tb – Tb0= Kb • bB
Kb : The constant of proportionality, (we called
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The freezing-point depression, ΔTf , is a colligative property of a solution equal to the freezing point of the pure solvent minus the freezing point of the solution.

chapter 1 Fluid Properties

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1.1 Definition of a Fluid
What is a fluid?
from a scientific or engineering point of view.
问题2：试问自由落体和加速度a向x方向运动状态下的液体所受的单位质量力大小（fX. fY. fZ）分别为多少？
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1.3 Fluid Properties
1.3.1.2 Suface Force pressu of a Fluid
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1.1 Definition of a Fluid
Some materials, such as slurries(泥浆), tar(柏油), putty(油灰, 灰泥), toothpaste, and so on, are not easily classified since they will behave as a solid if the applied shearing stress is small, but if the stress exceeds some critical
2

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1.3 Fluid Properties
Figure 1.2
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问题1：比较重力场（质量力只有重力）中，水和水银所受的单位质量力f水和f水银的大小？ A. f水<f水银； B. f水=f水银； C. f水>f水银； D、不一定。

流体力学C-名词解释

Chapter 1 Fluid statics 流体静力学1. 连续介质假定(Continuum assumption)：The real fluid is considered as no -gap continuousmedia, called the basic assumption of continuity of fluid, or the continuum hypothesis of fluid. 流体是由连续分布的流体质点(fluid particle)所组成，彼此间无间隙。

它是流体力学中最基本的假定，1755年由欧拉提出。

在连续性假设之下，表征流体状态的宏观物理量在空间和时间上都是连续分布的，都可以作为空间和时间的函数。

2. 流体质点（Fluid particle ）: A fluid element that is small enough with enough moles to makesure that the macroscopic mean density has definite value is defined as a Fluid Particle. 宏观上足够小，微观上足够大。

3. 流体的粘性（Viscosity ）: is an internal property of a fluid that offers resistance to sheardeformation. It describes a fluid's internal resistance to flow and may be thought as a measure of fluid friction. 流体在运动状态下抵抗剪切变形的性质，称为黏性或粘滞性。

它表示流体的部流动阻力，也可当做一个流体摩擦力量。

The viscosity of a gas increases with temperature, the viscosity of a liquid decreases with temperature. 4. 牛顿摩擦定律（Newton’s law of viscosity ）：5. The dynamic viscosity （动力黏度）is also called absolute viscosity （绝对黏度）. The kinematicviscosity （运动黏度）is the ratio of dynamic viscosity to density.6. Compressibility （压缩性）：As the temperature is constant, the magnitude ofcompressibility is expressed by coefficient of volume compressibility (体积压缩系数) к , a relative variation rate （相对变化率） of volume per unit pressure.The bulk modulus of elasticity (体积弹性模量) E is the reciprocal of coefficient of volumecompressibility к.7. 流体的膨胀性(expansibility; dilatability)：The coefficient of cubical expansion (体积热膨胀系数) αt is the relative variation rate of volume per unit temperature change.8. 表面力Surface tension : A property resulting from the attractive forces between molecules.σ-----单位长度所受拉力9. 表面力 Surface force ——is the force exerted on the contact surface by the contacted fluidor other body. Its value is proportional to contact area. 作用在所研究流体外表面上与表du dzτμ=μνρ=面积大小成正比的力。

华东理工大学过程装备与系统（双语）

华东理工大学过程装备与系统（双语）Chapter 1 Introduction to Process EquipmentKey TermsAxial bearings轴向轴承: devices designed to prevent back-and-forth movement of a shaft; also called thrust bearings.Boiler锅炉: a type of fired furnace used to boil water and produce steam; also known as a steam generator. Compressors 压缩机: mechanical devices designed to accelerate or compress gases; classified as positive displacement or dynamic.Coupling联轴器: a device that attaches the drive shaft of a motor or steam turbine to a pump, compressor, or generator.Driver: a device designed to provide rotational energy to driven equipment.Heat exchanger换热器: an energy-transfer device designed to transfer energy in form of heat from a hotter fluid to a cooler fluid without physical contact between the two fluids.Pumps泵: devices designed to move liquids from one place to another; classified as positive displacement or dynamic.Reactor反应器: a device used to combine raw materials, heat, pressure, and catalysts in the right proportions to form chemical bonds that create new products.Steam turbine蒸汽轮机: an energy-conversion device that converts steam energy(kinetic energy) to useful mechanical energy; used as drivers to turn pumps, compressors, and electric generators.Valve阀: a device used to stop, start, restrict(throttle), or direct the flow of fluids.Questions:1.Identify the purpose of a steam turbineThe purpose of a steam turbine is to converts kinetic energy to useful mechanical energy in order to drive pumps, compressors, and electric generators. (P9)2.Describe the importance of equipment lubrication.Lubrication protects the moving parts of equipment, helps remove heat generated and provides a fluid barrier between the metals parts to reduce friction, thus ensuring the good operation of process equipment. (P10)3.Explain the purpose of bearings and seals.Bearings prevent up-and-down and side-to-side or back-and-forth movement of a rotating shaft.Seals prevent leakage between internal compartments in a rotating piece of equipment. (P10)Rotary equipment uses seals and bearings to maintain operation integrity. (P20)4.What is the difference between rotary and stationary equipment?Rotary equipment is characterized by a circular movement and is composed of a driver, a connector, and the driven equipment. (P4)However, stationary equipment is static. (自己编的)5.How is power transmission in rotary equipment classified?Power transmission in rotary equipment is classified as speed-to-torque conversion or torque-to-speed conversion. (P6) Chapter 2 ValvesKey TermsCheck valves止回阀: mechanical valves that prevent reverse flow in piping.Control valves: automated valves used to regulate and throttle flow; typically provide the final control element of acontrol loop.Disc阀瓣: a device made of metal or ceramic that fits snugly in the seat of a valve to control flow.Gate valve闸阀: a device that places a movable metal gate in the path of a process flow.Globe valve止通阀: a device that places a disc in the path of a process flow.Safety/relief valve安全/释放阀: device set to a automatically relieve pressure in a closed system at apredetermined set point; relief valve valves are used for liquids; safety valves are used for gases. Stuffing box填料函: the section of a valve that contains packing.Throttling节流: reducing or regulating flow below the maximum output of a valve.Trim: the flow-control element and seats in a valve.Questions:6.Explain the purpose of valves in industrial manufacturing.The primary purpose of a valve is to direct and control the flow of fluids by starting, stopping, and throttling (restricting) flow to make processing possible. (P25)7.Identify the basic components of a gate valve.P27 Figure 2.28.List the main types of valves.Gate valves. Globe valves. Ball valves. Check valves. Butterfly valves. Plug valves. Diaphragm valves.Relief and safety valves. Automatic valves./doc/b718128130.html,pare a relief valve to a safety valve.Relief valve valves are used for liquids; safety valves are used for gases.10.List the four types of check valves.Swing check valve. Lift check valve. Ball check valve. Stop check valve.Chapter 3 Tanks, Piping, and VesselsKey TermsAlloy合金: a material composed of two or more metals or a metal and a nonmetal.Blind盲板: a device used in piping to gain complete shutoff.Butt-weld piping: pipe on which the parts to be joined are the same diameter and simply welded together. Corrosion腐蚀: electrochemical reactions between metal surfaces and fluids that result in the gradual wearing away of the metal.Flanges法兰: used to connect piping to equipment or where piping may have to be disconnected; consist of two mating plates fastened with bolts to compress a gasket between.Floating-roof tank: has an open top and a pan-like structure that floats on top of the liquid and moves up and down inside the tank with each change in liquid level.Grounding: is described as procedure designed to connect and object to the earth with a copper wire and a grounding rod.Radiographic inspection: use of X-rays to locate defects in metals in much the same manner as an X-ray is taken of a broken bone.Socket-welded piping: type of piping in which the pipe is inserted into a larger fitting before being welded to another part.Tank farm罐区: a collection of tanks used to store and transport raw materials and products. Questions:11.List the different types of aboveground storage found ina tank farm.Low, medium, high pressure. (P51)12.What two types of blinds do we use?Paddle blinds and figure-eight blinds. (P64)13.How does increased temperature affect the performance of metals?In general, as temperature increases, the strength of metals decreases and corrosion rate increases. (P66) 14.What is an alloy steel?Steel that contains alloy elements is called alloy steel. (自己编的)15.What is corrosion, and how is it manifested?Corrosion is electrochemical reactions between metal surfaces and fluids that result in the gradual wearing away of the metal (定义). In a word, corrosion is metal loss. (P60)Corrosion attack manifests itself in many ways, such as general loss of metal, pitting, grooving, cracking, or other kinds of selective attack. (P60)Chapter 4 PumpsKey TermsCentrifugal pumps离心泵: a dynamic pump that accelerates fluid in a circular motion.Impeller叶轮: a device attached to the shaft of a centrifugal pump that imparts velocity and pressure to a liquid.Positive displacement正位移、容积式: class of equipment such as pumps and compressors that move specific amounts of fluid from one place to another; can be rotary or reciprocating.Priming灌液: becoming filled with fluid.Pulsation dampener缓冲器: a device installed close to a pump, in the suction or discharge line, to reduce pressure variations.Reciprocating pump往复泵: a positive displacement pumpthat uses a plunger, piston, or diaphragm moving in a back-and-forth motion to physically displace a specific amount of fluid in a chamber.Rotary pump回转泵: a positive displacement pump that uses rotating elements to move fluids.Slip泄漏: the percentage of fluid that leaks or slips past the internal clearance of a pump over a given time. Vapor lock气缚: condition in which a pump loses liquid prime and the impellers rotate in vapor. Questions:16.Describe the scientific principles associated with centrifugal pump operation and identify keycomponents.P8917.List the various types of rotary pumps.Screw pump, external gear, internal gear, sliding vane, flexible vane, lobe pumps.18.List the various types of reciprocating pumps.Piston, plunger, diaphragm.19.What are the advantages of centrifugal pumps?Centrifugal pumps are cheaper and require less maintenance and space.They will operate with a constant head pressure over a wide capacity range.It is easier to change the element on a centrifugal pump than on a PD pump, and it is easier to change the driver.A final advantage is the adaptability of the selected driver----variable horsepower and fixed or variablespeed. (P92)Chapter 5 CompressorsKey TermsAftercooler后冷却器: a heat-exchange device designed to remove excess heat from the discharge side of a multistage compressor.Compression ratio: the ratio of discharge pressure(psia) to suction pressure(psia). Multistage compressors use a compression ratio in the 3 to 4 range, with the same approximate compression ratio in rach stage. Demister除雾器: a cyclone-type device used to swirl and remove moisture from a gas.Dryer: removes moisture from gas.Lobe compressor罗茨压缩机: a rotary compressor that contains kidney bean-shaped impellers.Oil separator: removes oil from compressed gases.Stage: each cylinder in a compressor; specifically, the area where gas is compressed.Questions:20.List the two types of compressors.Dynamic, positive displacement, thermal.21.List the three rotary compressors.Rotary screw, lobe compressor, liquid ring, sliding vane, scroll.22.List the basic components of a centrifugal compressor. P12123.List the main difference between a single-stage and a multistage compressor.Single-stage compressors compress the gas once, whereas multistage compressors deliver the discharge of one stage to the suction of another stage. Single-stage compressors are designed for high gas flow rates and low discharge pressures; multistage compressors are designed for high gas flow rates and high discharge pressures. (P121)24.What is the difference between dynamic and positivedisplacement compressors?Dynamic compressors operate by accelerating the gas and converting the energy to pressure. They can deliver much higher flow rates than PD compressors. Positive displacement compressors operate by trapping a specific amount of gas and forcing it into a smaller volume. (P140)Chapter 7 Heat ExchangersKey TermsCondenser冷凝器: a shell-and-tube heat exchanger used to cool and condense hot vapors.Conduction传导: the means of heat transfer through a solid, nonporous material resulting from molecular vibration. Conduction can also occur between closely packed molecules.Convection对流: the means of heat transfer in fluids resulting from currenst.Counterflow逆流: refers to the movement of two flow streams in opposite directions; also called countercurrent flow.Fixed head固定头: a term applied to a shell-and-tube heat exchanger that has the tube sheet firmly attached to the shell.Laminar flow层流: streamline flow that is more or less unbroken; layers of liquid flowing in a parallel path. Radiant heat transfer辐射传热: conveyance of heat by electromagnetic waves from a source to receivers. Reboiler再沸器: a heat exchanger used to add heat to a liquid that was once boiling until the liquid boils again.Shell-and-tube heat exchange管壳式换热器: a heat exchanger that has a cylindrical shell surrounding a tube bundle.Turbulent flow湍流: random movement or mixing in swirls and eddies of a fluid.Questions:25.What is a heat exchanger?A heat exchanger is an energy-transfer device designed to transfer energy in form of heat from a hotterfluid to a cooler fluid without physical contact between the two fluids. (第一章)26.What is meant by the term floating head?Floating head heat exchangers are designed for high temperature differentials above 200℉(93.33℃).During operation, one tube is fixed and the other “floats”inside the shell. The floating end is not attached to the shell and is free to expand. (P163)27.List five types of heat exchangers.Pipe coil exchangers, double-pipe heat exchangers, shell-and-tube heat exchangers, reboilers, plate-and-frame heat exchangers, air-cooled heat exchangers, spiral heat exchangers.28.Explain the purpose of using finned tubes in heat exchangers.Fins provide more surface area and allow greater heat transfer to take place. (P172)29.Contrast parallel and series flow through a heat exchanger.In series flow, the tube-side flow in a multipass heat exchanger is discharged into the tube-side flow of the second exchanger. This discharge route could be switched to shell side or tube side depending on how the exchanger is in service. The principle is that the flow passes through one exchanger before it goes to another. In parallel flow, the process flow goes through multiple exchangers at the same time.(P167)Chapter 8 Cooling TowersKey TermsAir intake louvers进风口: slats located at the bottom or sides of a cooling tower to direct airflow.Basin水池/槽: concrete storage compartment or catch basin located at the bottom of the cooling tower. Blowdown排污/清洗: a process of controlling the level of suspected solids in a cooling tower by removing a certain amount of water from the basin and replacing it with makeup water.Capacity可冷却的水量: the amount of water a cooling tower can cool.Cooling towers冷却塔: are evaporative coolers specifically designed to cool water or other mediums to the ambient wet-bulb air temperature.Drift eliminators收水器: devices used in a cooling tower to keep water from blowing out.Evaporate蒸发: to turn to vapor; evaporation removes heat energy from hot water.Forced-draft强制通风: type of mechanical-draft cooling tower that uses fans to push air into the tower. Induced-draft诱导通风: type of mechanical-draft cooling tower that uses fans to push air out of the tower. Questions:30.List and describe the basic components of a cooling tower.Water distribution header, splash bars, fill, basin, cooling water supply header, process exchangers, cooling water return header, drift eliminator. (P195自己看着抽出来的)31.Describe the relationship between heat exchangers and a cooling tower.In the manufacturing environment, heat exchangers and cooling towers work hand in hand to create a water-cooling system. Balabala… (P200)32.List five factors that affect the efficiency of a cooling tower.Evaporation, relative humidity, temperature, wind velocity, tower design, water contamination. (P194) 33.Which tower is most efficient: forced-draft or induced-draft? Why?Induced-draft. In an induced-draft cooling tower, the tower fan, located on the top of the tower, produces discharge rates strong enough to lift the hot air above the tower, so hot air is not recirculated into the tower. However, in a forced-draft cooling tower, the exiting air slows so much that it is recirculated back into the tower, cutting efficiency by 20%. (P198, 199)。

流体力学(英文课件)chap2

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Viscosity is a measure of a fluid's resistance to flow.
12
Fluid Mechanics 2010 CN Chapter 1
1. Physical characteristics
2. Viscosity (9)
5
1. Physical characteristics
2. Viscosity (2)
What is viscosity ?
Absolute viscosity is a measure of the resistance of a fluid to flow.
Higher viscosity: slower flow
Fluid Mechanics 2010 CN Chapter 1
10
1. Physical characteristics
2. Viscosity (7)
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Model of a laminar shear flow: Under the influence of a F tangential force F a pile of layers is sheared in x-direction. The top layer moves constantly at the velocity vx.
Basics of
Fluid Mechanics
Chapter 1: § 2 Viscosity
Marc Henn
Contents
1. Physical characteristics of fluids 1.2 Viscosity

The Physics of Fluids

The Physics of FluidsFluids are all around us. From the water we drink to the air we breathe, fluids are an integral part of our everyday lives. But have you ever stopped to think about what makes fluids behave the way they do? That is where the field of physics comes in. From the movement of fluids to the forces that act upon them, the physics of fluids is a fascinating subject that has far-reaching applications across a wide range of fields. In this article, we will explore some of the key principles that underpin the physics of fluids.What are Fluids?Before we dive into the physics of fluids, we need to first define what fluids are. Broadly speaking, a fluid is any substance that can flow and take the shape of its container. This includes liquids like water and gases like air. For the purposes of physics, fluids are often categorized based on their properties. For example, liquids are generally considered to be incompressible, meaning that their volume does not change significantly in response to changes in pressure. Gases, on the other hand, are compressible, meaning that their volume can be altered by changes in pressure. Understanding the properties of fluids is key to understanding the physics that governs their behavior.Fluid DynamicsOne of the most fundamental areas of study within the physics of fluids is fluid dynamics, which is concerned with the movement of fluids. This includes everything from the flow of water through a pipe to the way that air moves around an airplane wing. The movement of fluids is governed by a set of equations known as the Navier-Stokes equations, which describe the way that fluids respond to forces like pressure and friction. Solving these equations can be incredibly complex, and researchers have developed a range of methods for simulating fluid dynamics, from simple computer models to complex supercomputer simulations.One key concept within fluid dynamics is viscosity, which refers to the resistance of a fluid to flow. Liquids like honey and molasses are highly viscous, meaning that theyresist flow and require significant force to move. Gases, on the other hand, are typically less viscous and flow more easily. Understanding viscosity is important for a range of practical applications, from designing more efficient engines to improving the stability of industrial processes.Fluid ForcesFluids are subject to a range of forces that can influence their behavior. Some of the most important forces include pressure, buoyancy, and drag. Pressure arises when a fluid is confined, and is equal in all directions. This can result in interesting phenomena like Bernoulli's principle, which explains the way that air moves around a wing and is crucial for understanding the physics of flight. Buoyancy is the upward force exerted by a fluid on an object immersed within it, and is why objects float in water. Drag is the resistance experienced by an object moving through a fluid, and is a key consideration in the design of everything from cars to spacecraft.Applications of Fluid PhysicsThe principles of fluid physics have a wide range of applications across many different fields. One of the most obvious is in engineering, where fluid mechanics is essential for designing everything from engines to airplanes. Understanding fluid dynamics is also important for weather modeling and predicting natural disasters like hurricanes and floods. In the medical field, fluid mechanics plays a role in everything from blood flow to the dynamics of respiratory fluids. Other applications include everything from oil drilling to the design of microfluidic devices for use in the lab.ConclusionThe physics of fluids is a complex and fascinating subject with many different applications. From the movement of water through a pipe to the forces that act on a spacecraft during reentry, the principles of fluid physics have far-reaching implications for our world. By understanding the properties of fluids and the forces that act upon them, researchers are able to design more efficient engines, predict natural disasters withgreater accuracy, and even improve medical treatments. As our understanding of fluid physics continues to develop, the possibilities for its applications are truly endless.。

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。

physics of fluids

physics of fluidsPhysics of FluidsIntroduction:Fluids are an essential component of our daily lives. Whether it is the water we drink, the air we breathe, or the oil that powers our vehicles, fluids play a crucial role in various aspects of our existence. Understanding the behavior of fluids is important in numerous scientific and engineering disciplines. The field that studies the physics of fluids is known as fluid mechanics. In this document, we will explore the fundamental concepts and principles that govern the behavior of fluids.Properties of Fluids:Before delving into the physics of fluids, it is vital to understand the properties that define them. Fluids can be classified as liquids or gases. Liquids have a definite volume but take on the shape of their container, whereas gases have neither a definite volume nor shape. The density, viscosity, and compressibility of fluids are crucial properties that determine their behavior.Fluid Statics:Fluid statics deals with the study of fluids at rest. This branch of fluid mechanics considers fluids in equilibrium under the influence of external forces such as gravity. Key concepts in fluid statics include pressure, Pascal's principle, and Archimedes' principle. Pressure is defined as the force per unit area exerted by a fluid. Pascal's principle states that when an external pressure is applied to a confined fluid, the pressure is transmitted undiminished to all parts of the fluid. Archimedes' principle explains buoyancy, stating that an object submerged in a fluid experiences an upward force equal to the weight of the fluid displaced by the object.Fluid Dynamics:Fluid dynamics explores the behavior of fluids in motion. It focuses on studying the forces that act on fluids and predicting their behavior using mathematical equations. The fundamental equation that governs fluid flow is the Navier-Stokes equation. This equation describes the conservation of mass, momentum, and energy in fluids. It is notoriously complex to solve analytically and often requires computational techniques. Fluid dynamics encompasses various fascinating phenomena such as laminar and turbulent flow, boundary layers, and drag.Laminar and Turbulent Flow:Laminar flow refers to the smooth and orderly motion of fluid particles in layers, with minimal mixing between adjacent layers. It occurs at low flow rates and is characterized by predictable and steady behavior. On the other hand, turbulent flow is characterized by chaotic and irregular motion of fluid particles, with significant mixing occurring between different layers of the fluid. It usually occurs at high flow rates or in the presence of obstacles in the flow path. Turbulent flow is responsible for phenomena such as eddies, vortices, and enhanced heat and mass transfer.Boundary Layers:Boundary layers are thin layers of fluid that form along surfaces in contact with flowing fluids. They are essential in determining the drag force experienced by objects moving through fluids. The boundary layer can be categorized into two types: laminar boundary layer and turbulent boundary layer. The boundary layer concept is crucial in designing efficient aerodynamic shapes, as reducing drag is vital in various engineering applications.Drag:Drag is the resistance experienced by an object moving through a fluid. It is dependent on various factors such as the speed, shape, and roughness of the object, as well as the properties of the fluid. The drag force can be divided into twocomponents: skin friction drag and form drag. Skin friction drag arises due to the viscous effects of the fluid in direct contact with the object's surface. Form drag, on the other hand, is caused by the pressure distribution around the object and is influenced by its shape.Applications:The physics of fluids finds application in a wide range of fields. Some notable examples include aerodynamics, hydrodynamics, biomedical engineering, and environmental engineering. Understanding fluid behavior is essential in designing efficient aircraft, optimizing ship hull designs, studying blood flow in the human body, and predicting and managing natural disasters such as floods.Conclusion:The physics of fluids is a fascinating field that plays a critical role in several scientific and engineering disciplines. By studying the properties, behavior, and principles that govern fluids, scientists and engineers can design more efficient and sustainable systems. The concepts explored in this document provide a foundation for further exploration into the complex nature of fluid mechanics and its applications.。

热能动力工程专业英语

Professional English for Thermal Power Engineering
contents
目录
• Overview of Thermal Power Engineering
• Fundamentals of Thermal Power Engineering
• Professional vocabulary for thermal power engineering
Application fields of thermal power engineering
Power generation
Thermal power plants are the main way of power generation, accounting for a large promotion of global electricity production
• Integration with information technology: The integration of thermal power engineering with information technology allows for more effective monitoring, control, and optimization of thermal power plants
• Radiation Heat Transfer: Radiation heat transfer occurs when electromagnetic waves transfer energy between objects Understanding radiation heat transfer is important for designing heat exchanges and other thermal systems

Chapter 1,2 Fluid Mechanics作业

Chapter 1 Fluid Mechanics1-2.The reading of the vacuum gauge in an equipment is 100mmHg, try to calculate the absolute pressure and the gauge pressure, respectively. It is known that the atmospheric pressure in this area is 740mmHg.1-3.As shown in the figure, the reservoir holds the oil with a density of 960kg/m³. The oil level is 9.6m higher than the bottom of the reservoir. The pressure above the oil level is atmospheric pressure. There is a round hole with a diameter of 760mm at the lower part of the sidewall, the center of which is 800mm higher than the bottom of the reservoir. The hole cover is fixed with steel bolts (Φ14mm). If the working stress of the bolts is 400kgf/cm2,how many bolts should be used ?1-4. There are two U-tube differential pressure meters fixed on the fluid bed reactor, as shown in the figure. It is measured that the reading is R1=400mm，R2=50mm, respectively. The indicating liquid is mercury. To avoid the mercury vapor diffusing in the air, water is injected in the U-tube which is connected with air on the right side, and the height R3=50mm. Try to calculate the pressure at point A and B.1-5.As shown in the figure, the manometric tubes are connected with the equipment A , B, C, respectively. The indicating liquid in the tubes is mercury, while on the top of the tube is water, water surface of the three equipments is at the same level. Try to determine:1)Is the pressure equal with each other at the point 1, 2 and 3?2)Is the pressure equal with each other at the point 4, 5 and 6?3)If h1=100mm, h2=200mm, and equipment A is open to the atmosphere (the atmospheric pressure is 760mmHg), try to calculate the pressure above the water surface in equipment B and C.1-6. As shown in the figure, the steam pressure above the boiler is measured with the U-tube differential pressure meters in series. The indicating liquid in the differential pressure meter is mercury, the connecting tube between the two U-tube meters is full of water.Given that the vertical distance between the mercury levels and the referring level is h 1=2.3m, h 2=1.2m, h 3=2.5m, h 4=1.4m respectively. The vertical distance between the water level in the boiler and the base level is h 5=3m. The atmospheric pressure Pa is 745mmHg. Try to calculate the vapor pressure P 0 above the water level in the boiler.(inN/m²，respectively.)2/364400m N1-7. Based on the reading of the differential pressure meter as shown in the figure, calculate the gauge pressure of the gas in the tube line. The indicating liquids in the differential pressure meter are oil and water, with the density of 920kg/m³ and 998kg/m³, respectively. The distance between the water and oil interfaces in the U-tube R is 300mm. The inner diameter of the expansionchambers is 60mm, and that of the U-tube is 6mm . When the gas pressure in the tube line is equal to the atmospheric pressure, the liquid level in the two expansion chambers is even with each other. 20m /N 257003.081.99203.081.9)920998(P =⨯⨯+⨯⨯-=1-8. The tube bundle of a tubular heat exchanger is constituted of 121 steel tubes (Φ25×2.5mm). The air with an average temperature of 50℃ flows in the tube bundle at 9m/s. The pressure of the air is 2kgf/cm²(gauge pressure). The local atmospheric pressure is 740mmHg . Try to calculate :1) The mass flow of the air;（质量流量）2) The volume flow rate of the air under the operation condition;（体积流量）1-9. The gas at the average pressure of 1atm flows in the pipe (Φ76⨯3mm). Now the average pressure is changed to 5atm , if it is required that the gas flows at the same temperature, rate and mass velocity , what should the inside diameter of the tube be?1-10. The feeding liquid with a density of 850kg/m³ is sent into the tower from the elevated tank （储槽）. The liquid level in the elevated tank keeps constant. The gauge pressure in the tower is 0.1kgf/cm², and the feeding rate is 5m³/h . The connecting pipe issteel pipe (Φ38⨯2.5mm), the energy loss in the connecting pipe of the feed liquid is 30J/kg (the energy loss in the exit is not included). What is the distance between the liquid level of the elevated tank and the feeding inlet?1-11. The water level in the elevated tank is 8m highe r than the floor. Water flows out of the pipeline (Φ108⨯4mm), of which the outlet is 2m higher than the floor. Under the given condition, the energy loss of the water flowing through system (the energy loss of the outlet is not included) can be calculated with Σh f=6.5u², where u is the water velocity (in m/s). Try to calculate:1)The water velocity at the section A-A’;2)The flow rate of water (in m3/h).1-12. Water with a temperature of 20℃ flows through the horizontal pipe (Φ38⨯2.5mm) at 2.5m/s . The pipe is connected with another horizontal pipe (Φ53⨯3mm) t hrough a conical pipe. As shown in the figure, two vertical glass tubes are inserted at section A and B on either side of the conical pipe, respectively. If the energy loss when water flows through section A and B is1.5J/kg, try to calculate the distance between the two water levels in the glass tubes (in mm)? Draw out the relative position of the water level in the figure.O m m H p p A B 26.88798.9/5.868==-A B p p >1-13. Water at 20℃ is sent to the top of the scrubber from the reservoir with a centrifugal pump. The water level in the reservoir keeps constant, as shown in the figure. The diameter of the pipeline is Φ76⨯2.5mm. Under the operation condition, the reading of the vacuum gauge at the pump entrance is 185mmHg . The energy loss when water flows through the suction tube (The entrance of the pipe is not included) and the discharge tube can be calculated according to formula Σh f,1=2u² and Σh f‚2=10u², where u is the water velocity in the suction or discharge tube. The gauge pressure at thejoint of the discharged tube and the spray nozzle is 1kgf/cm 2. Try to calculate the effective power of the pump. kW W w W N s e e 26.2226092.74.285==⨯==1-15. A cooling brine circulating system is shown in the figure. The density of the brine is 1100kg/m³, and the circulation is 36m³/h. The diameter of all the pipelines is the same. The energy loss when the brine flows from point A to B through two heat exchangers is 98.1J/kg, and the loss when the brine flows from B to A is 49J/kg. Try to calculate:1) If the efficiency of the pump is 70%, what is the shaft power of it?(in kw)2) If the reading of the manometer at point A is 2.5kgf/cm², what is the reading of the manometer at point B?1-17. Liquid with a density of 850kg/m³, and a viscosity of 8cp flows in the steel pipe (the inside diameter is 14mm). The liquid velocity is 1m/s. Try to calculate:1) The Reynolds number, and point out the flow pattern.2) The position where the local velocity is equal to the average velocity.3) Suppose the pipeline is a horizontal pipe, and the pressure of the upstream is 1.5kgf/cm², How long the liquid has to flow through when the pressure drop to 1.3kgf/cm²?1-18. As shown in the figure, an inverse U-tube differential pressure meter is fixed between the cross sections of two horizontal pipes with different diameters in order to measure the pressure difference of the two cross sections. When the flow rate is 10800kg/h, the reading of the differential pressure meter is 100mm. The diameters of the two pipe are Φ60⨯3.5mm and Φ42⨯3mm, respectively. Calculate :1) The energy loss of 1kg water flowing through the two cross sections;2） The pressure drop which is correspondent to the energy loss (in N/m²).1-19. Liquid is flowing laminarly in a straight pipe. If the pipelength and the physical property keeps constant, with the diameter decreases to half of the original, how many times is the energy loss aroused by the flow resistance as much as the original?1-22.Liquid is sent to the elevated tank from the reactor with a pump at 2⨯104kg/h (as shown in the figure). The pressure above the liquid surface in the reactor keeps a vacuum of 200mmHg, and that above the liquid surface in the elevated tank is the atmospheric pressure. The pipeline is the steel pipe(Φ76⨯4mm), with the length of 50m. There are two wide open brake valves, a orifice meter (the resistance coefficient is 4), five standard elbows in the pipeline. The vertical distance from the liquid surface in the reactor to the exit of the pipeline is 1.5m. If the efficiency of the pump is 0.7, try to calculate the shaft power of the pump. It is given that the density of the liquid is 1073kg/m³, the viscosity is 0.63cP, and the absolute roughness of the pipe wall ε is 0.3mm.1-23. There are a few solvents in the exhaust gas discharged from the equipment. Before vented to the atmosphere, the gas is sent through a washing tower in order to recover the solvents and avoid the environmental pollution. The flow rate of gas is 3600m³/h (under the operation condition), and the physical property of gas is almost the same as that of air at 50℃. As shown in the figure, a U-tube differential pressure meter with the indicating liquid ofwater is fixed in the pipeline before the gas entering the blower. The reading of the meter is 30mm. The inside diameters of both the delivering pipe and the venting pipe are 250mm. The total equivalent length of the pipe line, fitting, and valves is 50m (The resistance of entering and leaving the tower is not included),and the vertical distance between the vent and the entrance of the blower is20m. Suppose the pressure drop of the gas through the filler layer in the tower is 200mm H2O, the absolute roughness of the pipe wall εcan be taken as 0.15mm and the atmospheric pressure is 1atm, try to calculate the effective power of t he blower （风机）.1-24.As shown in the figure, the water level in the reservoir keeps constant. A steel drainpipe (with the inside diameter of 100mm) is connected to the bottom of the reservoir. There is a gate valve fixed in the pipeline, and a U-tube differential meter with the indicating liquid of mercury is fixed at the position 15m away from the entrance of the pipeline. One part of the differential meter is connected to the pipe, and the other is connected to air. The connecting tube of the differential pressure meter is full of water. The length of the straight pipe between the pressure measuring point and the outlet of the pipeline is 20m.a)When the gate valve is closed, R=600mm, h=1500mm; when the gate valve is opened partly, R=400mm, h=1400mm. The friction coefficient λ is 0.025, and the local resistance coefficient at the entrance of the pipeline is 0.5. Calculate the flow rate of water when the gate valve is opened partly. (in m³/h)b)When the gate valve is widely open, calculate the static pressure at the pressure measuring point (in gauge pressure, N/m²). It is given that le/d≈15when the gate valve is widely open, and the frict ion coefficient λ is still 0.025.2）The pressure at the pressure measuring point when the gate valve is widely open.1-26.Water at 20℃passes through a steel pipe with an insidediameter of 300mm. There is a branch pipe(Φ60 3.5mm) which is parallel with the main pipe. The total length including all the local frictional loss of the branch pipe is 10m. A rotameter is fixed in the branch pipe. From the rotameter, the flow rate of water is 2.72m3/h. Try to calculate the flow rate in the main pipe and the total flow rate, respectively. The frictional coefficient of the main pipe and the branch pipe is 0.018 and 0.03, respectively.Chapter 2 Fluid Transportation2-1. water is used in the experiment to measure the property of pump. As the flow rate is 26m3/h, the reading of piezometer at the exit of the pump is 152 kPa and the reading of vacuum gauge at the entry of the pump is 24.7 kPa.The shaft power is 2.45kw, rotational speed is 2900r/min, respectively. If the vertical distance between the vacuum meter and piezometer is 0.4m, the pipeline diameters of the entry and exit of pump are the same. The frictional resistance between two gauges is negligible. Calculate the efficiency of pump and list the performance of the pump under this efficiency.2-2. Hot water at 60℃in reservoir is sent by a centrifugal pump at the flow rate of 40m3/h to thetop of a cooling water tower, then is sprayed by a sprayer and drops into a cooling reservoir，so that the hot water is cooled. Given the gage pressure maintains 49kPa before water enter the sprayer, the inlet of sprayer is 0.5m above the level of hot water in the reservoir. The total head loss of inhalation pipeline and vent pipeline is 1m and 3m respectively, and the kinetic head in pipeline can be negligible.Try to select a fitting centrifugal pump and determine the installation height. Suppose the local atmosphere pressure is 101.33kPa.（=3.77m）2-3. Oil products are filled in a groove under the normal pressure, the density is 760kg/m3, absolute viscosity is less than 20cp. Under the operating condition, the saturated vapor pressure is 80kPa. Now the oil would be sent by 65Y-60B oil pump into an equipment in which the gauge pressure is 1.8mH2O. The level of oil in the groove is invariability. The entry of the equipment is 5m above the level of oil in the groove. The total heads loss of inlet pipeline and outlet pipeline is 1m and 4m respectively. Try to calculate whether the pump can work normally.If the oil pump is 1.2m below the level of oil in the groove, whether the pump can be operated normally? Suppose the local atmosphere pressure is 101.33kPa.Based on the table of textbook, the capability of 65Y-60B oil pump is listed as followsFlow rate, m³/h 19.8Total head, m 38Shaft power, kW 3.75Efficiency, % 55Cavitation, m 2.6（65Y-60B oil pump is operable ）.m H g 74.016.281.976010)8.00133.1(5-=--⨯⨯-= The actual suction lift is -1.2m < -0.74m, which means the pump can operate normally .。

流体力学(英文资料)

A380 73×79.8× 24.2 (m)
An-225 84×88.4×18.1 (m)
How can an airplane fly?
A turbofan(涡扇) jet engine
；
CFM56 in MTU
What is Fluid Mechanics ?
Fluid Mechanics is the study of fluid either in motion (Fluid Dynamics 流体动力学) or at rest(Fluid Statics 流体静力学) and subsequent effects of the fluid upon the boundaries, which may be either solid surfaces or interfaces with other fluids.
Ludwig Prandtl (1875-1953)
Boundary layer theory(1904)
To be the single most important tool in modern flow analysis.
The father of modern fluid mechanics
19th century
Navier (1785-1836) & Stokes (1819-1905)
N-S equation
Reynolds (1842-1912) Turbulence Famous experiment on transition Reynolds Number
20th century
Any shear stress applied to a fluid, no matter how small, will result in motion of that fluid. The fluid moves and deforms continuously as long as the shear is applied.

Fluent中英对照

Aabort 异常中断, 中途失败, 夭折, 流产, 发育不全，中止计划[任务] accidentally 偶然地, 意外地accretion 增长activation energy 活化能active center 活性中心addition 增加adjacent 相邻的aerosol浮质(气体中的悬浮微粒,如烟,雾等), [化]气溶胶, 气雾剂, 烟雾剂Air flow circuits 气流循环ambient 周围的, 周围环境amines 胺amplitude 广阔, 丰富, 振幅, 物理学名词annular 环流的algebraic stress model(ASM) 代数应力模型algorithm 算法align 排列，使结盟, 使成一行alternately 轮流地analogy 模拟，效仿analytical solution 解析解anisotropic 各向异性的anthracite 无烟煤apparent 显然的, 外观上的，近似的approximation 近似arsenic 砷酸盐assembly 装配associate 联合，联系assume 假设assumption 假设atomization 雾化axial 轴向的Axisymmetry 轴对称的BBaffle 挡流板battlement 城垛式biography 经历bituminous coal 烟煤blow-off water 排污水blowing devices 鼓风(吹风)装置body force 体积力boiler plant 锅炉装置（车间）Boiling 沸腾Boltzmann 玻耳兹曼Bounded central differencing：有界中心差分格式Brownian rotation 布朗转动bulk 庞大的bulk density 堆积密度burner assembly 燃烧器组件burnout 燃尽Ccapability 性能，（实际）能力，容量，接受力carbon monoxide COcarbonate 碳酸盐carry-over loss 飞灰损失Cartesian 迪卡尔坐标的casing 箱，壳，套catalisis 催化channeled 有沟的，有缝的char 焦炭、炭circulation circuit 循环回路circumferential velocity 圆周速度clinkering 熔渣clipped 截尾的clipped Gaussian distribution 截尾高斯分布closure (模型的)封闭cloud of particles 颗粒云close proximity 距离很近cluster 颗粒团coal off-gas 煤的挥发气体coarse 粗糙的coarse grid 疏网格，粗网格Coatingcoaxial 同轴的coefficient of restitution 回弹系数；恢复系数coke 碳collision 碰撞competence 能力competing process 同时发生影响的competing-reactions submodel 平行反应子模型component 部分分量composition 成分computational expense 计算成本cone shape 圆锥体形状configuration 布置，构造confined flames 有界燃烧confirmation 证实, 确认, 批准Configuration 构造，外形conservation 守恒不灭conservation equation 守恒方程conserved scalars 守恒标量considerably 相当地consume 消耗contact angle 接触角contamination 污染contingency 偶然, 可能性, 意外事故, 可能发生的附带事件continuum 连续体Convection 对流converged 收敛的conveyer 输运机convolve 卷cooling duct 冷却管cooling wall 水冷壁coordinate transformation 坐标转换correlation 关联(式)correlation function 相关函数corrosion 腐蚀，锈coupling 联结, 接合, 耦合Cp：等压比热crack 裂缝，裂纹creep up （水）渗上来，蠕升critical 临界critically 精密地cross-correlation 互关联cumulative 累积的curtain wall 护墙，幕墙curve 曲线custom 习惯, 风俗, <动词单用>海关, (封建制度下)定期服劳役, 缴纳租税, 自定义, <偶用作>关税v.定制, 承接定做活的Cyan青色cyano 氰（基），深蓝，青色cyclone 旋风子，旋风，旋风筒cyclone separator 旋风分离器[除尘器]cylindrical 柱坐标的cylindrical coordinate 柱坐标Ddead zones 死区decompose 分解decouple 解藕的defy 使成为不可能Deforming：变形demography 统计Density：密度deposition 沉积derivative with respect to 对…的导数derivation 引出, 来历, 出处, (语言)语源, 词源design cycle 设计流程desposit 积灰，结垢deterministic approach 确定轨道模型deterministic 宿命的deviation 偏差devoid 缺乏devolatilization 析出挥发分，液化作用diffusion 扩散diffusivity 扩散系数digonal 二角(的), 对角的，二维的dilute 稀的diminish 减少direct numerical simulation 直接数值模拟discharge 释放discrete 离散的discrete phase 分散相, 不连续相discretization [数]离散化deselect 取消选定dispersion 弥散dissector 扩流锥dissociate thermally 热分解dissociation 分裂dissipation 消散, 分散, 挥霍, 浪费, 消遣, 放荡, 狂饮distribution of air 布风divide 除以dot line 虚线drag coefficient 牵引系数，阻力系数drag and drop 拖放drag force 曳力drift velocity 漂移速度driving force 驱[传, 主]动力droplet 液滴drum 锅筒dry-bottom-furnace 固态排渣炉dry-bottom 冷灰斗，固态排渣duct 管dump 渣坑dust-air mixture 一次风EEBU---Eddy break up 漩涡破碎模型eddy 涡旋effluent 废气，流出物elastic 弹性的electro-staic precipitators 静电除尘器emanate 散发, 发出, 发源，[罕]发散, 放射embrasure 喷口，枪眼emissivity [物]发射率empirical 经验的endothermic reaction 吸热反应enhance 增，涨enlarge 扩大ensemble 组，群，全体enthalpy 焓entity 实体entrain 携带，夹带entrained-bed 携带床Equation 方程equilibrate 保持平衡equilibrium 化学平衡ESCIMO-----Engulfment（卷吞）Stretching（拉伸）Coherence（粘附）Interdiffusion-interaction（相互扩散和化学反应）Moving-observer（运动观察者）exhaust 用尽, 耗尽, 抽完, 使精疲力尽排气排气装置用不完的, 不会枯竭的exit 出口，排气管exothermic reaction 放热反应expenditure 支出，经费expertise 经验explicitly 明白地, 明确地extinction 熄灭的extract 抽出，提取evaluation 评价，估计，赋值evaporation 蒸发(作用)Eulerian approach 欧拉法Ffacilitate 推动，促进factor 把…分解fast chemistry 快速化学反应fate 天数, 命运, 运气，注定, 送命，最终结果feasible 可行的，可能的feed pump 给水泵feedstock 填料Filling 倒水fine grid 密网格，细网格finite difference approximation 有限差分法flamelet 小火焰单元flame stability 火焰稳定性flow pattern 流型fluctuating velocity 脉动速度fluctuation 脉动，波动flue 烟道（气）flue duck 烟道fluoride 氟化物fold 夹层块forced-and-induced draft fan 鼓引风机forestall 防止Formulation:公式，函数fouling 沾污fraction 碎片部分，百分比fragmentation 破碎fuel-lean flamefuel-rich regions 富燃料区，浓燃料区fuse 熔化，熔融Ggas duct 烟道gas-tight 烟气密封gasification 气化(作用)gasifier 气化器Gauge 厚度，直径，测量仪表，估测。

Chapter 2 Concept and definition

20:34:17
Fundamentals MHM Transfer
1
Fluid
A fluid is defined as a substance which deforms continuously under the action of shear stress.
Liquids and gases
d (V ) 0 dt
Unsteady flow:If the flow at a point varies with
time.
d (V ) 0 dt
Stationary，at rest
Dynamic or motion
20:34:18
Fundamentals MHM Transfer
12
Incompressible flow
The three fundamental laws of physics. Lagrangian representation. Eularian representation. Continuum. Give an example of a compressible fluid. Fluid property and flow property Gradient and dot product
20:34:18
Fundamentals MHM Transfer
11
Steady and unsteady flows
Steady flow: The flow conditions are independent
of time at every point in the flow fields
(2) The macroscopic properties of a continuum are consider to vary smoothly from point to point in the fluid.

流体力学C-名词解释

Chapter 1 Fluid statics 流体静力学1. 连续介质假定(Continuum assumption)：The real fluid is considered as no-gapcontinuous media, called the basic assumption of continuity of fluid, or the continuum hypothesis of fluid. 流体是由连续分布的流体质点(fluid particle)所组成，彼此间无间隙。

它是流体力学中最基本的假定，1755年由欧拉提出。

在连续性假设之下，表征流体状态的宏观物理量在空间和时间上都是连续分布的，都可以作为空间和时间的函数。

2. 流体质点（Fluid particle ）: A fluid element that is small enough with enoughmoles to make sure that the macroscopic mean density has definite value is defined as a Fluid Particle. 宏观上足够小，微观上足够大。

3. 流体的粘性（Viscosity ）: is an internal property of a fluid that offers resistanceto shear deformation. It describes a fluid's internal resistance to flow and may be thought as a measure of fluid friction. 流体在运动状态下抵抗剪切变形的性质，称为黏性或粘滞性。

它表示流体的内部流动阻力，也可当做一个流体摩擦力量。

The viscosity of a gas increases with temperature, the viscosity of a liquid decreases with temperature.4. 牛顿内摩擦定律（Newton ’s law of viscosity ）：5. The dynamic viscosity （动力黏度）is also called absolute viscosity （绝对黏度）.The kinematic viscosity （运动黏度）is the ratio of dynamic viscosity todensity.6. Compressibility （压缩性）：As the temperature is constant, the magnitude ofcompressibility is expressed by coefficient of volume compressibility (体积压缩系数) к , a relative variation rate （相对变化率） of volume per unit pressure.The bulk modulus of elasticity (体积弹性模量) E is the reciprocal of coefficient7. 流体的膨胀性(expansibility; dilatability)：The coefficient of cubicalexpansion (体积热膨胀系数) αt is the relative variation rate of volume per unit temperature change.du dzτμ=μνρ=8. 表面张力Surface tension : A property resulting from the attractive forcesbetween molecules. σ-----单位长度所受拉力9. 表面力 Surface force ——is the force exerted on the contact surface by thecontacted fluid or other body. Its value is proportional to contact area. 作用在所研究流体外表面上与表面积大小成正比的力。

工程热力学与传热学(英文) 第8章热量传递的基本方式

Heat Transfer
--- Chapter 8 Basic Modes of
Heat Transfer ---
Chapter 8 Basic Modes of Heat Transfer
Contents

Conduction heat transfer and Fourier’s law of onedimensional steady state heat-conduction Convection heat transfer and Newton’s law of cooling Radiation heat transfer and Stefan-Boltzmann Law Heat transfer processes
Heat transfer
• To tell how long it takes to reach this equilibrium condition
（需要多长时间达到平衡状态, 即热传播的速率）
• To predict the temperature of both the bar and the water as a function of time.（钢棒和水的温度随时间的变化规律）
8-3 Radiation（热辐射）
8-3-1 Some definitions（热辐射的有关概念）
1. 辐射：是指物体受某种因素的激发而向外发射辐射能的现象。
受热，电子碰撞，光照，化学反应等
According to electromagnetic theory（电磁理论） The propagation of thermal radiation takes place in the form of electromagnetic wave. （辐射能是由电磁波传输的能量）

Chapter2_FLOW-3D几何模型导入及网格划分

• 三角面缺失严重的图问题无法利用 pyADMesh 修补
pyADMesh显示
打开file C:\class\demo_files\ Spillway_Missing_tri.STL
• 内定的选项
– – – – Close gaps Add triangles to fill holes Fix unit normal directions Fix unit normal values
• 如何决定 sub-component 要加入到现有的或新的component?
• 相同的材料与运动性质设成同一个 component!
Blue – dam structure, smooth surface Orange – topography, rough surface Dark Blue – north gate, moving
•屏幕适合尺寸视图
Unit 单位
• FLOW-3D 采用单位为 – SI（m, Kg, …） – CGS（cm, g, …） – ENGINEERING（英制） • 由于大部分铸件绘图单位为 mm，因此在 FLOW-3D 导入几何时建议将单位转换至 CGS 制。 • 1 mm = 0.1 cm，因此单位转换时 Global magnitude 必须填入 0.1。
注意图形导入顺序
• 如果两个subcomponents/components有重迭部分，重迭区域的性质以先加载的图形为主
Solid
Subcomponent/Component 1
Solid
Subcomponent/Component 2
Solid
Subcomponent/Component 1
Solid

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流体力学Fluid Mechanics 蒋文涛副教授Tel：85405140 scubme@推荐参考资料•流体力学•高等土木工程专业指导委员会规划推荐教材•刘鹤年主编•中国建筑工业出版社•/ycjx/fluid•清华大学《工程流体力学》网络课程•其它用于土木工程专业的中、英文《工程流体力学Engineering Fluid Mechanics》或《流体力学Fluid Mechanics》教材•其它学校的网络课程，如浙江大学•我校精品课程网《水力学》Chapter 2 Properties of Fluid流体的微观和宏观特性•流体分子微观运动自身热运动•流体团宏观运动外力引起统计平均值流体质点概念•为了符合数学分析的需要，引入流体质点模型(1)流体质点无线尺度，无热运动，只在外力作用下作宏观平移运动;(2) 将周围临界体积范围内的分子平均特性赋于质点。

•为了描述流体微团的旋转和变形引入流体质元（流体元）模型：(1)流体元由大量流体质点构成的微小单元（δx，δy，δz）；(2) 由流体质点相对运动形成流体元的旋转和变形运动。

连续介质假设•连续介质假设：假设流体是由连续分布的流体质点组成的介质。

(1)可用连续性函数B(x,y,z,t)描述流体质点物理量的空间分布和时间变化；(2)由物理学基本定律建立流体运动微分或积分方程，并用连续函数理论求解方程。

•连续介质假设模型是对物质分子结构的宏观数学抽象，就象几何学是自然图形的抽象一样。

•除了稀薄气体与激波的绝大多数工程问题，均可用连续介质模型作理论分析。

流体的易变形性•流体与固体在宏观力学行为方面的主要差异是流体具有易变形性。

•流体的易变形性表现在：▲在剪切力持续作用下，流体能产生无限大的变形；▲在剪切力停止作用时，流体不作任何恢复变形；▲在流体内部压强可向任何方向传递；▲任意搅拌的均质流体，不影响其宏观物理性质；▲粘性流体在固体壁面满足不滑移条件；▲在一定条件下流体内部可形成超乎想象的复杂结构；粘性（Viscosity）•Resistance to shear or angular deformation •Related to molecular activities1. 流体内摩擦概念牛顿在《自然哲学的数学原理》(1687)中指出：相邻两层流体作相对运动时存在内摩擦作用,称为粘性力。

•库仑实验(1784)库仑用液体内悬吊圆盘摆动实验证实流体存在内摩擦。

流体的粘性•流体粘性形成原因:(1)两层液体之间的粘性力主要由分子内聚力形成(2)两层气体之间的粘性力主要由分子动量交换形成流体的粘性(续）2. 壁面不滑移假设由于流体的易变形性，流体与固壁可实现分子量级的粘附作用。

通过分子内聚力使粘附在固壁上的流体质点与固壁一起运动。

Real fluids, even though they may be moving, always “stick”to the solid boundaries that contain them.•库仑实验间接地验证了壁面不滑移假设；•壁面不滑移假设已获得大量实验证实，被称为壁面不滑移条件。

牛顿在《自然哲学的数学原理》中假设：“流体两部分由于缺乏润滑而引起的阻力，同这两部分彼此分开的速度成正比”。

即在图中，粘性切应力为γμμτ&==yud d 上式称为牛顿粘性定律，它表明：•牛顿粘性定律已获得大量实验证实。

⑴粘性切应力与速度梯度成正比；⑵粘性切应力与角变形速率成正比；⑶比例系数称动力粘度，简称粘度。

r&G =τ•与固体的虎克定律作对比：牛顿粘性定律•牛顿内摩擦定律切应力和剪切（角）变形速率之间存在正比例关系比例系数称为动力粘性系数，是粘性流体的物理属性。

•容易解释为什么是剪切（角）变形速率，它表示流体直角减小的速度。

τyud d d d u yτμ=μyud d1.动力粘度（Dynamic Viscosity）粘度的单位是Pa •s (帕秒）或kg/m •s常温常压下，水和空气的粘度系数分别为空气水＝μμ4.55粘度poise ＝0.1 Pa•sps Pa 01.01013=⋅×=−μps pa 00018.0108.15=⋅×=−μ水：空气：γτμ&=Coefficient ofDynamic viscosity is the fluid property that relates shearing stress and fluid motion.动力粘性系数•物理意义•反映了流体抵抗剪切变形能力的大小•Dynamic viscosity is the fluid property that relates shearing stress and fluid motion.•量纲：•单位（SI ）：μ11L MT−−Pa s⋅2.运动粘度(kinematical viscosity)ρμν=常温常压下，水和空气的粘度系数分别为空气水＝νν15/1运动粘度的单位是s/m 2scm s m /01.0/101226=×=−scm s m /15.0/1015225=×=−νν水：空气：粘度（Viscosity ）运动粘性系数•物理意义：由于运动粘性系数是动力粘性系数与密度之比，它的值已不能反映各种流体间粘性的大小•量纲：•单位(SI)：μνρ=21L T−2/ m s量纲和单位（Dimensions & Units）•Dimension: Generalizationof “unit”telling us whatkind of units are involvedin a quantitative statement•Mass [M], length [L], time [T]•Unit: Particular dimension•kg, m, s(Systeme International)•slug, ft, s(British Gravitational)•lbf, ft, s(something else)[]⎥⎦⎤⎢⎣⎡=⎥⎦⎤⎢⎣⎡=2 2TLMTMLm aF rr根据粘性对流体的分类The various types of non-Newtonian fluids aredistinguished by how theirapparent viscosity changeswith shear rate.流体粘性随温度的变化•Viscosity is verysensitive to temperature.•液体：温度升高，粘性减小•气体：温度升高，粘性增大流体粘性随温度的变化流体的可压缩性1、流体的密度()0δd ,,,lim δd m m x y z t τρττΔ→==常温下取ρ水=1000 kg / m 3ρ空气= 1.2 kg/m 3流体的可压缩性：在外力作用下流体密度（体积）发生改变的的性质。

描述流体可压缩性的物理量，除密度外还有（1）体积模量d d /p K ττ=−（2）声速ρK /c =常温下，1480 m / s340 m / s＝水c ＝空气c 流体的其他物理性质表面张力1.表面张力通常是指液体与气体交界面上的张应力2. 表面张力现象：⑵洗洁剂⑶毛细现象⑷微重力环境行为⑴肥皂泡R p σ2=Δ)11(21R R p +=Δσ密度（Density）•单位体积的质量(e.g., @ 20o C, 1 atm)•Waterγwater= 1000 kg/m3•MercuryγHg= 13,600 kg/m3•Airγair= 1.22 kg/m3•液体的密度在同一温度、不同压力下几乎不变（不可压缩性）•单位体积的重量(e.g., @ 20 o C, 1 atm)Defined as weight per unit volume.γwater = (1000 kg/m 3)(9.807 m 2/s)= 9807 N/m 3[= 62.4 lbf/ft 3]ρ= γ / g]/[]/[33ft lbf or m N g ργ=比重（Specific gravity ）•Dimensionless ratioliquid liquid waters ρρ=比容（Specific Volume）•The volume occupied by a unit mass of fluid1v=ρ体积弹性模量（Bulk modulus）•Liquids are usually considered to be incompressible, whereas gases compressible.•Bulk modulus•Table 2.1•Sample Prob. 2.3 ()v dp vE v dpdv dv=−=−Perfect Gas Law •State Equationppv RT==ρPerfect Gas Law •State Equation: Between Different States•For isothermal •For isentropic1n=.npv Const=pvcn kc==Standard Atmosphere流体模型按粘性分类无粘性流体粘性流体牛顿流体非牛顿流体按可压缩性分类可压缩流体不可压缩流体其他分类完全气体正压流体斜压流体均质流体等熵流体恒温流体流体模型分类。

Chapter2 Properties of Fluid(3)

Amesim 液压仿真学习

Chapter 2 Propertities of Fluids

溶液稀释英文版的教学课件 CHAPTER 2

chapter 1 Fluid Properties

流体力学C-名词解释

华东理工大学过程装备与系统（双语）

流体力学(英文课件)chap2

The Physics of Fluids

Glider Flying Handbook说明书

physics of fluids

热能动力工程专业英语

Chapter 1,2 Fluid Mechanics作业

流体力学(英文资料)

Fluent中英对照

Chapter 2 Concept and definition

流体力学C-名词解释

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