过程装备与控制工程专业英语翻译(部分)
过程装备与控制工程专业英语
5
The design of chemical reactors is probably the one activity which is unique to chemical engineering, and it is probably this function more than anything else which justifies the existence of chemical engineering as a distinct branch of engineering.
Physical treatment Steps
Produces
Recycle
1
The raw materials undergo a number of physical treatment steps to put them in the form in which they can be reacted chemically. They then pass through the reactor.The products of the reaction must then undergo further physical treatment- separations, purifications, etc. - for the final desired product to be obtained. 原料进行了一些物理处理的步骤，使它们能够发 生化学反应。然后让他们通过反应器。产物要经 历进一步的物理处理——分离，净化提纯等等， 以获得期望的最终产品。
只有……才有的 化学反应器的设计也许是一种只有化学工程领域才涉及 的工作。并且可能正是因为这种功能才奠定了化学工程 作为工程领域的一个特殊分支而存在的合理性
过程装备与控制工程英语
过程装备与控制工程英语1.过程装备(Process equipment)The process equipment in the factory is responsible for manufacturing products efficiently.2.控制工程(Control engineering)Control engineering plays a crucial role in ensuring the stability and reliability of industrial processes.3.设备(Equipment)The factory invested in state-of-the-art equipment to improve production efficiency.4.流程(Process)The production process includes multiple stages, each with its own specific requirements.5.控制(Control)The control system allows operators to monitor and adjust various parameters for optimal performance.6.自动化(Automation)Automation has greatly improved efficiency in manufacturing processes.7.传感器(Sensor)Sensors are used to collect real-time data and provide feedback for control purposes.8.测量(Measurement)Accurate measurement of process variables is crucial for maintaining quality standards.9.监控(Monitoring)Continuous monitoring of process parameters is essential for early detection of issues.10.仪表(Instrumentation)Instrumentation plays a vital role in collecting and displaying data from various sensors in a process.11.采样(Sampling)Regular sampling of raw materials ensures their quality meets the required standards.12.环境监测(Environmental monitoring)Efficient control engineering systems enable real-time environmental monitoring.13.压力(Pressure)The pressure in the system is carefully controlled to ensure stable operation.14.温度(Temperature)Temperature control is crucial for maintaining the desired chemical reaction rate.15.流量(Flow rate)Monitoring and controlling the flow rate of liquid or gas is important for process efficiency.16.液位(Liquid level)Accurate measurement of liquid level ensures proper functioning of the process.17.控制阀(Control valve)Control valves regulate the flow rate or pressure offluid in a process.18. PLC (Programmable Logic Controller)PLCs are widely used in control engineering to automate and monitor industrial processes.19.数据采集(Data acquisition)Data acquisition systems collect and record data from various sensors for analysis.20.仪器仪表校准(Instrument calibration)Regular instrument calibration ensures accurate measurement and control.21.故障诊断(Fault diagnosis)Advanced control engineering systems can detect and diagnose faults in real-time.22.实时控制(Real-time control)Real-time control engineering allows for immediate adjustments to process conditions.23.可靠性(Reliability)Reliability is a key factor in choosing process equipment and control systems.24.自适应控制(Adaptive control)Adaptive control algorithms constantly adjust process parameters to optimize performance.25.能源管理(Energy management)Efficient control engineering strategies can help optimize energy consumption in industrial processes.。
过程装备与控制工程专业专业英语翻译9
Reading Material 9Heat Treatment of SteelTypes of Heat Treating Operations Five operations are detailed in this lesson as the basis of heat treatment. Explanations of theseOperations follow.Stress Relieving When a metal Is heated， expansion occurs which is more or less proportional to the temperature rise. Upon cooling a metal,the reverse reaction takes place. That is, a contraction is observed．When a steel bar or plate is heated at one point more than at another，as in welding or during forging，Internal stresses are set up．During heating, expansion of the heated area cannot take place unhindered，and it tends to deform．On cooling，contraction is prevented from taking place by the unyielding cold metal surrounding the heated area．The forces attempting to contract the metal are not relieved，and when the metal is cold again，the forces remain as internal stresses．stresses also result from volume changes, which accompany metal transformations and precipitation．Internal or residual stresses are bad because they may cause warping of steel parts when they are machined．To relieve these stresses，steel is heated to around 5950C，assuming that the entire part is heated uniformly, then cooled slowly back to room temperature．This procedure is called stress relief annealing, or merely stress relieving.Because of characteristics inherent in cast steel, the normalizing treatment is more frequently applied to ingots prior to working， and to steel castings and forgings prior to hardening.Normalizing The process of normalizing consists of heating to a temperature above the third transformation temperature and allowing the part to cool in still air. The actual temperature required for this depends on the composition of the steel, but is usually around 8700C. Actually, the term normalize does not describe the purpose. The process might be more accurately described as a homogenizing or grain-refining treatment. Within any piece of steel, the composition is usually not uniform throughout. That is, one area may have more carbon than the area adjacent to it. These compositional differences affect the way in which the steel will respond to heat treatment. If it is heated to a high temperature, the carbon can readily diffuse throughout, and the result is a reasonably uniform composition from one area to the next. The steel is then more homogeneous and will respond to the heat treatment in a more uniform way.During cold deformation, steel has a tendency to harden in deformed areas, making it more difficult to bend and liable to breakage. Alternate deforming and annealing operations are performed on most manufactured steel products.Full annealing Full annealing, where steel is heated 50 to 100C above the third transformation temperature for hypoeutectoid steels, and above the lowest transformation temperature for hypereutectoid steels, and slow cooled, makes the steel much easier to cut, as well as bend. In full annealing, cooling must take place very slowly so that a coarse pearlite is formed. Slow cooling is not essential forprocess annealing, since any cooling rate from temperatures below the lowest transformation temperature will result in the same microstructure and hardness.Process annealing Process annealing consists of heating steel to a temperature just below the lowest transformation temperature for a short time. This makes the steel easier to form. This heat treatment is commonly applied in the sheet and wire industries, and the temperatures generally used are from 550 to 650C.Annealing The two--stage heat treating process of quenching and tempering is designed to produce high strength steel capable of resisting shock and deformation without breaking. On the other hand, the annealing process is intended to make steel easier to deform or machine. 1n manufacturing steel products, machining and severe bending operations are often employed. Even tempered steel may not cut or bend very easi1y and annealing is often necessary.The effect of tempering may be il1ustrated as follows. If the head of a hammer were quenched to a fully martensitic structure, it probably would crack after the first few blows. Tempering during manufacture of the hammer imparts shock resistance with only a slight decrease in hardness. Tempering is accomplished by heating a quenched part to some point below the transformation temperature, and holding it at this temperature for an hour or more, depending on its size. Most steels are tempered between 205°C and 595°C. As higher temperatures are employed, toughness or shock resistance of the steel is increased, but the hardness and strength decrease.Tempering Ductility is the ability of a metal to change shape before it breaks. Fleshly quenched martensite is hard but not ductile; in fact, it is very brittle. Tempering is needed to impart ductility to the martensite, usually at a small sacrifice in strength. In addition, tempering greatly increases the resistance of martensite to shock loading.Heat Treatment The hardest condition for any given steel is obtained by quenching to a fully martensitic structure. Since hardness is directly related to strength, a steel composed of 100% martensite is at its strongest possible condition. However, strength is not the only property that must be considered in the application of steel parts. Ductility may be equally important.Change or modify the magnetic properties of steel.Improve the electrical properties;Improve the machinability;Increase the toughness; that is, to produce a steel having both a high tensile strength and good ductility, enabling it to withstand high impact ;Increase the hardness so as to increase resistance to wear or to enable the steel to withstand more service conditions;Decrease the hardness and increase the ductility;Secure the proper grain structure ;Refine the grain structure of hot worked steels which may have developed coarse grain size ;Remove stresses induced by cold working or to remove stresses set up by nonuniform cooling of hot metal objects;Reasons for Heat Treating Heat treatment of steel is usually intended to accomplish any one of the following objectives:Stress relieving Stress relieving is the heating of steel to a temperature below the transformation temperature, as in tempering, but is done primarily to relieve internal stress and thus prevent distortion or cracking during machining. This is sometimes called process annealing.Tempering Tempering consists of reheating a quenched steel to a suitable temperature below the transformation temperature for an appropriate time and cooling back to room temperature. How this process makes steel tough will be discussed later.Hardening Hardening is carried out by quenching a steel, that is, cooling it rapidly from a temperature above the transformation temperature. Steel is quenched in water or brine for the most rapid cooling, in oil for some alloy steels, and in air for certain higher alloy steels. After steel is quenched, it is usually very hard and brittle; it may even crack if dropped. To make the steel more ductile, it must be tempered.Normalizing Normalizing is identical with annealing, except that the steel is air cooled; this is much faster than cooling in a furnace. Steel is normalized to refine grain size, make its structure more uniform, or to improve machinability. Full annealing Full annealing is the process of softening steel by a heating and cooling cycle, so that it may be bent or cut easily. In annealing, steel is heated above a transformation temperature and cooled very slowly after it has reached a suitable temperature. The distinguishing characteristics of full annealing are: (a) temperature above the critical temperature and (b) very slow cooling, usually in the furnace.阅读材料9钢的热处理各种不同的热处理操作本单元介绍了五种热处理的基本方法。
过程装备与控制工程专业英语翻译14
Reading material 14Evaporation1． IntroductionThe objective of evaporation is to concentrate a solution consisting of a nonvolatile solute and a volatile solvent. In the overwhelming majority of evaporations the solvent is water. Evaporation is conducted by vaporizing a portion of the solvent to produce a concentrated solution of thick liquor. Evaporation differs from drying in that the residue is a liquid-sometimes is highly viscous one-rather than a solid; it differs from distillation in that the vapor usually is a single component, and even when the vapor is a mixture, no attempt is made in the evaporation step to separate the vapor into fractions; it differs from crystallization in that emphasis is placed on concentrating a solution rather than forming and building crystals. In certain situations, e.g., in the evaporation of brine to produce common salt, the line between evaporation and crystallization is far from sharp. Evaporation sometimes produces a slurry of crystal in a saturated mother liquor.Normally, in evaporation the thick liquor is the valuable product and the vapor is condensed and discarded. In one specific situation, however, the reverse is true. Mineral-bearing water often is evaporated to give a solid-free product for boiler feed, for special process requirements, or for human consumption. This technique is often called water distillation, but technically it is evaporation. Large-scale evaporation processes have been developed and used for recovering potable water from seawater. Here the condensed water is the desired product. Only a fraction of the total water in the feed is recovered, and the remainder is returned to the sea.2. Liquid CharacteristicsThe practical solution of an evaporation problem is profoundly affected by the character of the liquor to be concentrated. It is the wide variation in liquor characteristics (which demands judgment and experience in designing and operating evaporators) that broadens this operation from simple heat transfer to a separate art. Some of the most important properties of evaporating liquids are as follows. Concentration Although the thin liquor fed to an evaporator may be sufficiently dilute to have many of the physical of water, as the concentration increases, the solution becomes more and more individualistic. The density and viscosity increase with solid content until either the solution becomes saturated or the liquor becomes too viscous for adequate heat transfer. Continued boiling of a saturated solution causes crystals to form; these must be removed or the tubes clog. The boiling point of the solution may also rise considerably as the solid content increases, so that the boiling temperature of a concentrated solution may be much higher than that of water at the same pressure.FoamingSome materials, especially organic substances, foam during vaporization. A stable foam accompanies the vapor out of the evaporator, causing heavy entertainment. In the extreme cases, the entire mass of liquid may boil over into the vapor outletand be lost.Temperature sensitivity Many fine chemicals pharmaceutical products, and foods are damaged when heated to moderate temperatures for relatively short times. In concentrating such materials special techniques are needed to reduce both the temperature of the liquid and the time of heating.Scale Some solutions deposit scale on the heating surface. The overall coefficient then steadily diminished, until the evaporator must be shut down and the tubes cleaned. When the scale is hard and insoluble, the cleaning is difficult and expensive.Materials of construction Whenever possible, evaporator are made of some kind of steel. Many solutions, however, attack ferrous metals or are contaminated by them. Special materials such as copper, nickel, stainless steel, aluminum, imperious graphite, and lead are then used. Since these materials are expensive, high heat transfer rates become especially desired to minimize the first cost of the equipment. Many other liquid characteristics must be considered by the designer of an evaporator. Some of these are specific heat, heat of concentration, freezing point, gas liberation on boiling, toxicity, explosion hazards, radioactivity, and necessity for sterile operation. Because of the variation in liquor properties, many different evaporator designers have been developed. The choice for any specific problem depends primarily on the characteristics of the liquid.3. Single and multiple-effect operationMost evaporators are heated by steam condensing on the metal tubes. Nearly always the material to be evaporated flows inside the tubes. Usually the steam is at low pressure, below 3 atm abs; often the boiling liquid is under moderate vacuum, at pressure down to about 0.05 atm abs. Reducing the boiling temperature of the liquid increase the temperature difference between the steam and the boiling liquid and thus increase the heat transfer rate in the evaporator.When a single evaporator is used, the vapor from the boiling liquid is condensed and discarded. This method is called single-effect evaporation, and although it is simple, it utilizes steam ineffectively. To evaporate 1 kg water from a solution call for from 1 to 1.3 kg of steam. If the vapor from one evaporator is fed into steam chest of a second evaporator and the vapor from second is then sent to a condenser, the operation becomes double-effect. The heat in the original steam is reused in the second effect, and the evaporation achieved by a unit mass of steam fed to the first effect is approximately doubled. Additional effects can be added in the same manner. The general method of increasing the evaporation per kilogram of steam by using a series of evaporator between the steam supply and the condenser is called multiple-effect evaporation.4. General types of evaporatorHorizontal-tube natural circulation evaporator the horizontal bundle of heating tubes is similar to the bundle of tubes in a heat exchanger. The steam enters into the tubes, where it condenses. The steam condensate leaves at the other end of the tubes. The boiling liquid solution covers the tubes. The vapor leaves the liquid surface, often goes through some deentraining device such as a baffle to preventcarryover of liquid droplets, and leaves out the top. This type is relatively cheap and is used for no viscous liquid having high heat transfer coefficients and liquids that do not deposit scale. Since liquid circulation is poor, they are unsuitable for viscous liquid. In almost all cases, this evaporator and the types discussed below are operating continuously, where the feed enters at a constant rate and the concentrate leaves at a concentrate rate.Vertical-type natural circulation evaporator in this type of evaporator, vertical rather than horizontal tubes are used, and the liquid is inside the tubes and the steam condenses outside the tubes. Because of boiling and decreases in density, the liquid rises in the tubes by natural circulation and flows downward through a large central open space or downcomer. This natural circulation increases the heat transfer coefficient. It is not used with viscous liquid. This type is often called the short-tube evaporator. A variation of this is the basket type. Where vertical tubes are used, but the heating element is held suspended in the body so there is an annular open space as the downcomer. The basket type differs from the vertical natural circulation evaporator, which has a central instead of annular open space as the downcomer, this type is widely used in the sugar, salt, and caustic soda industries.Long-tube vertical-type evaporator since the heat transfer coefficient on the steam side is very high compared to that on the evaporating liquid side, high liquid velocities are desirable. In a long-tube vertical-type evaporator the liquid is inside the tubes. The tubes are 3 to 10 m long and the formation of vapor bubbles inside the tubes causes a pumping action giving quite high liquid velocities. Generally, the liquid passes through the tubes only once and is not reticulated. Contact times can be quite low in this type. In some case,as when the ratio of the feed to evaporation rate is low.Natural recirculation of the product through the evaporators done by adding a large pipe connection between the outlet concentrate line and the feed line. This is widely used for producing condensed milk. Falling-film evaporator a variation of the long tube type is the falling-film evaporator, wherein the liquid is fed to the top of the tubes and flows down the walls as a thin film. Vapor-liquid separation usually takes place at the bottom. This type is widely used for concentrating heat-sensitive material such as orange juice and the other fruit juices, because the holdup time is very small (5 to 10 s or more).and the heat-transfer coefficients are high.Forced-circulation type evaporator this liquid film heat transfer coefficient can be increased by pumping to cause forced circulation of the liquid inside the tubes. This could be done in the long tube vertical type by adding a pipe concentrate with a pump between the outlet concentrate line and the feed line. However, usually in a forced-circulation type, the vertical tubes are shorter than in the long-tube type. Also, in other cases a separate and external horizontal heat exchanger is used. This type is very useful for viscous liquids.阅读材料14蒸发1、介绍蒸发的目的是浓缩不易挥发的溶质和易挥发的溶剂组成的溶液。
过程装备与控制工程专业英语翻译Part.Ⅳ(课文+阅读材料)综合各版精华
PART IV 过程装备█Unit 16压力容器及其部件压力容器是不泄露的容器。
它们被制造成各种尺寸和形状。
较小的直径也许还不到一英寸，而较大的直径则可能达到150英尺甚至更大。
某些压力容器被掩埋在地下或海洋深处，但大多数都被安放在地面上或支撑在平台上，实际上，还有一些可以在航天飞机中的储罐和液压装置中找到。
由于内部压力，过程装备被设计为各种形状和尺寸。
内部压力可能低到1in，水的表面压力可能达到300000psi（磅/平方英寸）或更高。
一般单层式结构的承压范围是大约15psi到5000psi，尽管有很多容器的设计压力低于或高出这个范围。
ASME锅炉和压力标准在第八篇第一分册中提出了一个以15psi为下限且不设上限的内压范围，然而根据ASME VIII-I，当内压超过3000psi时，进行特殊的设计考量也是必要的。
压力容器的典型部件描述如下：圆柱壳体在石油化学工业中，圆柱壳体非常频繁的被用来构造压力容器。
圆柱壳体容易制造和安装，并且维护保养起来经济。
壳体所需壁厚通常由内压决定，但在某些情况下是由外加载荷和外压决定的。
其他因素如热应力和不连续压力也可能影响到壳体所需壁厚。
成型封头对于设计工程师来说，各种各样的封头和过渡部分都是可以被采用的。
使用某种结构而不是另一种取决于很多因素，比如成型方法、材料成本和空间限制。
一些常用的成型封头是：带凸缘的封头这些封头通常用于在低压下工作的压力容器中，例如汽油罐和锅炉。
有些也应用在较高压力但直径较小的设备中。
其设计和制造的大量细节由ASME标准第八章第一分册给出。
半球形封头通常，在一个给定的温度和压力下，半球形封头所需的厚度是相同直径和材料圆柱壳体的一半。
当使用像镍和钛这样昂贵的合金制造时（不论是实心的还是镀层的），半球形封头是很经济的。
然而在使用碳钢时，由于高额的制造费用，半球形封头就不像帯凸缘的和碟形的封头经济。
半球形封头通常由分段的三角形部件拼成或通过旋压制造。
过程装备与控制工程专业英语翻译5
Reading Material 5Static and Dynamic Balance of Rotating BodiesThe unbalance of a single disk can detected by allowing the disk to rotate on its axle between two parallel knife-edges, as shown in Fig.1.22. The disk will rotate and come to rest with the heavy side on the bottom. This type of unbalance is called static unbalance, since it can be detected by static means.In general, the mass of a rotor is distributed along the shaft such as in a motor armature or an automobile-engine crankshaft. A test similar to the one above many indicate that such parts are in static balance, but the system may show a considerable unbalance when rotated.As an illustration, consider a shaft with two disks, as shown in Fig. l. 23. If the two unbalance weights are equal and 180 deg. apart, the system will be statically balanced about the axis of the shaft. However, when the system is rotated, each unbalanced disk would set up a rotating centrifugal force tending to rock the shaft on its bearings. Since this type of unbalance results only from rotation we refer to it as dynamic unbalance.Fig. 1. 24 shows a general case where the system is both statically and dynamically unbalanced. It will now be shown thatthe unbalanced forces P and Q can always be eliminated by the addition of two correction weights in any two parallel planes of rotation.Consider first the unbalance force P, which can be replaced by two parallel forces and . In a similar manner Q can be replaced by two parallel forces and . The two forces in each plane can then be combined into a single resultant force that can be balanced by a single correction weight as shown. The two correction weights C1 and C2 introduced in the two parallel planes completely balanced P and Q, and the system is statically and dynamically balanced. It should be further emphasized that a dynamically balanced system is also statically balanced. The converse, however, is not always true; a statically balanced system may be dynamically unbalanced.Example A rotor 4 in. long has an unbalance of 3 oz.in. in a plane 1 in. from the left end, and 2 oz. in. in the middle plane. Its angular position is 90 deg. in the clockwise direction from the first unbalance when viewed from the left end. Determine the corrections in the two end planes, giving magnitude and angular positions.Solution. The 3-oz. in. unbalance is equivalent to oz. in. at the left end and oz. in. at the right end, as shown in Fig. 1. 25. The 2 oz. in. at the middle is obviously equal to l oz. in. at the ends.Combining the two unbalances at each end, the corrections are: Left end:OZ.in.to be removedclockwise from plane of first unbalanceRight end:OZ.in.to be removedclockwise from plane of first unbalance第一个不平衡点的逆时针方向阅读材料 5旋转体的静态和动态平衡单一圆盘的失衡可以通过使平行于轴的两根刃行支撑的转动来检测到，如图1.22所示。
过程装备与控制工程专业英语翻译1
过程装备与控制工程专业英语本文为过程装备与控制工程专业英语的个人翻译尝试。
By LiyerPART 1 engineering mechanicUnit 1 introduction to mechanicof materials材料力学是应用力学的分支，用于解决固体遭受外部多种载荷产生的力学行为。
对这个课题领域的另外的称呼有材料强度与固体变形的力学。
本章节提及固体包括经受轴向载荷的杆、扭转的轴、弯曲的梁和被压缩的圆柱。
材料力学研究的主要目标是在外部载荷加载的时候确定结构的应力、压力和应变以及固体微元的具体变化。
如果能够得到物体从受载到失效的所有与载荷对应的这些物理量，我们就对物体的力学性能有了一个全面的了解。
对力学行为的理解对于各种类型结构的安全设计是十分必要的，不管是飞机和天线、建筑和桥梁、机器和发动机、或者是船和飞行器。
这就是材料力学在这么多工程领域里都属于基础学科的原因。
静力学和动力学也是基本的，但是这些学科主要解决与粒子和刚体相关的力和运动问题。
在材料力学中，我们可以通过检测一个在有限维度内受力变形的实物的应力和应变来进一步学习。
而为了确定应力和应变，我们一般使用材料的物理性质以及一些理论公式和概念。
理论分析和实验结果在材料力学中也扮演着重要的角色。
我们从理论中为预测力学状态导出了准则和公式，但这些表达方式不能被用于实际的设计中，除非材料的物性已知。
只有通过在实验室细心的实验测试，我们方能得到材料的物性。
而且，并不是所有实际问题都能通过理论分析来解决，在这种情况下，物性试验就是必要的了。
材料力学的发展是理论和实验的有趣的结合-理论有时候指明了可以得到重大进展的路，有时候实验也做到这一点。
一些著名的科学家，如Leonardo da Vinci和Galileo Galilei通过实验确定绳索、杆和梁等的强度，尽管从今天的观点，他们没有得出详尽的理论体系来解释他们的实验结果。
相反的，著名的数学家Leonhard Euler在1744年得出了圆柱体的数学理论并且计算了圆柱体的临界载荷，远早于任何能够证明他的结果重要性的实验证据出现。
过程装备与控制工程专业英语翻译1
The reactions for th1.2 (c)]can be found the same manner
For the cantilever beam[Fig.1.2(b)], the action of the applied load q is equilibrated by a verticalforce RAand a couple MAacting at the fixed support, as shown in the figure. From a summationof forces in vertical direction , we include that
过程装备与控制工程专业英语全部翻译
General Equilibrium Conditions of A System力系的一般平衡条件在这一部分，我们将研究为了使一个物体保持平衡，作用在其上的力和力偶所必须满足的条件。
根据牛顿第一定律，施加在一个静止物体上的力系的合力一定为零。
然而，请注意这个定律对力矩或力系的转动效应只字未提。
显然，合力矩也一定为零，否则物体将会转动。
这里的基本问题是原先叙述的牛顿第一定律（和第二定律）只适用于非常小的物体，或者尺寸可以忽略的非零质量的粒子。
然而，它可以扩展到如下所述的有限尺寸的物体。
考虑一个由两个质点组成的系统，假设1f 和2f 为它们之间的相互作用力(图.1.1)。
这些力称为内力，因为它们是由于系统内部的物体之间的相互作用而产生的。
假定内力服从牛顿第三定律，我们有12f f =-。
假如还有质点与系统外物体之间的相互作用力施加在质点上，如1,2F F 和3F ,这些力称为外力。
显然，作用在一个特定粒子上的力一定有相同的应用，因为粒子的尺寸可以忽略。
如果系统内的每一个质点处于平衡，我们就可以说系统是平衡的。
在本例中，依据牛顿第一定律，作用在每个质点上的力的合力一定为零。
对质点A 我们有：∑=++=0121f F F F A 而对质点B 有：∑032=+=F f F B作用在系统上的力的总和为：123120A B F F F F F F f f =+=++++=∑∑∑现在我们来研究这些力对于同一点P 的合力矩。
由图1.1，我们有：12()()P A B M r F r F =⨯+⨯∑∑∑ 由于力1f 和2f 有相同的作用线，力矩的条件可以改写为1121223()0P M r F F f f r F =⨯++++⨯=∑ 但12f f =-；所以力和力矩的条件简化为1210F F F F +=+=∑ 和111223()()()0P M r F r F r F =⨯+⨯+⨯=∑换句话说，如果系统处于平衡，那么作用在其上的合外力一定为零，而且这些力对于任一点的合力矩也为零。
过程装备与控制工程专业英语
第四单元Membrane Stresses薄膜应力Shells of Revolution回转壳体Curve曲线 Axis轴线Process vessels过程容器 Cylinder cylindrical 圆柱,圆柱的Cone conical圆锥 ,圆锥的Hemispherical sphere半球形的,球形 Ellipsoidal椭圆形的 T orispherical准球形的（碟形的）Bending stresses弯曲应力 Shear stresses剪切应力 Internal pressure内压Arising from…由什么引起Be subjected to…承受…Symmetric对称的Circumference周向的 Meridional stress经向应力 Circumferential stress周向应力T angential stress切向应力 Radius of curvature曲率半径 Normal component法向分量Diameter直径 An angle αto the axis与轴夹角α段落： 22页2，3段第五单元mechanical vibration机械振动 periodically repeated motion交替重复的运动 wear磨损bear轴承 fatigue疲劳 precision instrument精密仪表 propeller螺旋桨threshing machine脱粒机 spring弹簧 shaft轴 beam梁 cantilever beam悬臂梁cycle循环 frequency频率 amplitude振幅 displacement位移 elastic force弹性力free vibration自由振动 natural frequency自然频率 forced vibration受迫振动exciting force激振力 damped vibration阻尼振动 undamped vibration非阻尼振动degree of freedom自由度 coordinate坐标重点段落：图1.20下面的第一段:"Mechanical vibrations ...for many purposes."第六单元金属合金 metal alloy 结晶的crystalline 晶格crystal-lattice 原子atom 离子ions锻造金属wroung metal 铸造金属cast metal 导热体conductor of heat导电体conductor of electricity 塑性的plastic 黑色金属ferrous metal 铸铁cast iron有色金属nonferrous metal 碳钢carbon steel 铜合金copper alloy 钛trtanium熔点melting point第七单元原材料 the virgin/starting material 韧性ductility 脆性brittleness 断裂fracture硬化hardening 导热性 thermal conduction 润滑(n,v）lubrication ,lubricateThe final strength of any material used in an engineering component depends on its mechanical and physical properties after it has been subjected to one or more different manufacturing processes. 用于工程构件的任何一种材料的最终强度取决于这种材料在经历了一种或多种不同加工过程之后的机械与物理性质。
过程装备与控制工程课后材料专业英语翻译
装控091专业英语翻译unit 1Static Analysis of BeamsA bar that is subjected to forces acting trasverse to its axis is called a beam. In this section we Will consider only a few of the simplest types of beams, such as those shown in Flag.1.2. In every instance it is assumed that the beam has a plane of symmetry that is parallel to the plane of the figure itself. Thus the cross section of the beam occurs in that plane. Later we will consider a more general kind of bending in which the beam may have an unsymmetrical cross section.The beam in Fig.1.2, with a pin support at one end and a roller support at the other, is called a simply support beam ,or a simple beam . The essential feature of a simple beam is that both ends of the beam may rotate freely during bending, but the cannot translate in lateral direction. Also ,one end of the beam can move freely in the axial direction (that is, horizontal). The supports of a simple beam may sustain vertical reactions acting either upward or downward .The beam in Flg.1.2(b) which is built-in or fixed at one end and free at the other end, is called a cantilever beam. At the fixed support the beam can neither rotate nor translate, while at the free end it may do both. The third example in the figure shows a beam with an overhang. This beam is simply supported at A and B and has a free at C.Loads on a beam may be concentrated forces, such as P1 and P2 in Fig.1.2(a) and (c), or distributed loads loads, such as the the load q in Fig.1.2(b), the intesity. Distributed along the axis of the beam. For a uniformly distributed load, illustrated in Fig.1.2(b),the intensity is constant; a varying load, on the other hand, is one in which the intensity varies as a function of distance alongthe axis of the beam.The beams shown in Fig.1.2 are statically determinate because all their reactions can be determined from equations of static equilibrium. For instance ,in the case of the simple beam supporting the load P 1 [Fig.1.2(a)], both reactions are vertical, and tehir magnitudes can be found by summing moments about the ends; thus, we findL a L P R A )(1-=LL P R B 1= The reactions for the beam with an overhang [Fig.1.2 (c)]can be found the same manner.For the cantilever beam[Fig.1.2(b)], the action of the applied load q is equilibrated by a vertical force RA and a couple MA acting at the fixed support, as shown in the figure. From a summation of forces in certical direction , we include thatqb R A =， And ,from a summation of moments about point A, we find)2(b a qb M A +=， The reactive moment MA acts counterclockwise as shown in the figure.The preceding examples illustrate how the reactions(forces and moments) of staticallydeterminate beams requires a considerition of the bending of the beams , and hence this subject will be postponed.The idealized support conditions shown in Fig.1.2 are encountered only occasionally in practice. As an example ,long-span beams in bridges sometimes are constructionn with pin and roller supports at the ends. However, in beams of shorter span ,there is usually some restraint against horizonal movement of the supports. Under most conditions this restraint has little effect on the action of the beam and can be neglected. However, if the beam is very flexible, and if the horizonal restraints at the ends are very rigid , it may be necessary to consider their effects.Example*Find the reactions at the supports for a simple beam loaded as shown in fig.1.3(a ). Neglect the weight of the beam.SolutionThe loading of the beam is already given in diagrammatic form. The nature of the supports is examined next and the unknow components of reactions are boldly indicated on the diagram. The beam , with the unknow reaction components and all the applied forces, is redrawn in Fig.1.3(b) to deliberately emphasiz this important step in constructing a free-body diagram. At A, two unknow reaction components may exist , since roller. The points of application of all forces are carefully noted. After a free-body diagram of the beam is made, the equations of statics are applied to abtain the sollution.∑=0x F ，R Ax =0∑+=0A M ，2000+100（10）+160（15）—R B =0，R B =+2700lb ↑∑+=0BM ,RAY(20)+2000—100（10）—160（5）=0，RAY=—10lb ↓ Check ：∑+↑=0FX ，—10—100—160+270=0Note that ∑=0x F uses up one of the three independent equations of statics, thus only twoadditional reaction compones may be determinated from statics. If more unknow reaction components or moment exist at the support, the problem becomes statically indeterminate.Note that the concentrated moment applied at C enters only the expressions for summation moments. The positive sign of RB indicates that the direction of RB has been correctly assumed in Fig.1.3(b). The inverse is the case of RAY ,and the vertical reaction at a is downward. Noted that a check on the arithmetical work is available if the caculations are made as shown.Reading materia l一条受力作用沿着横向坐标的轴类称作横梁。
过程装备与控制工程专业英语翻译10
Reading Material 10Corrosion ControlCorrosion problems can be solved in the following ways:(1) Select a material that is resistant to be the corrosion environment.(2) Give metal a protective coating.(3) Change the service conditions, such as temperature, pressure, or velocity.(4) Change the environment chemistry such as pH, concentration, aeration, or impurities.(5) Add a corrosion inhibitor.(6) Shift the electric potential of the metal by cathodic or anodic protection(7) Modify the design of the equipment or system.(8) Let it corrode and replace it (often a viable alternative!)Once the engineer has determined that there is no danger of a catastrophe, deciding which way to combat corrosion usually comes down to the economics of the situation.Material SelectionStainless steels are usually the first choice for a “probably corrosive”environment with unknown properties, because these alloys are resistant to a wide range of oxidizers, but they cannot withstand strong reducing solutions, such as hydrochloric acid. Stainless steels can be corroded, despite their name. The stainless steels are classified into five general groups (martensitic, ferritic, austenitic, duplex and precipitation-hardenable strainless steels) according to their metallurgical structures, with the of which one to use depending not only on corrosion resistance but also on required strength and cost.Commercially pure nickel has high corrosion resistance, especially to alkalies, combined with mechanical properties similar to mild steel, and good weldability. Nickel and nickel alloys widely used in the food industry and are frequently selected for service in chlorine, hydrogen chloride, and chlorinated hydrocarbons. They are very resistant to high-temperature air and to stress-corrosion cracking. Aluminum is a very reactive metal in the standard electromotive force series; it immediately reacts with air to form a passive film consisting of two layers: an inner, compact, amorphous oxide and an outer, thicker, more permeable hydrated oxide. Aluminum is naturally compatible with the atmosphere and withstands many solutions well if the pH lies between about 4 to 9. Strong acids and moderately strong bases destroy aluminum’s passive film. Chloride ions are particularly damaging because they attack the film only at weak spots and pit aluminum. Many chlorinated organic solvents and alcohols can attack aluminum alloys disastrously, sometimes explosively.Protective CoatingsThe major purpose of coating a metal is to protect it from a corrosive environment when the metal is otherwise suitable for the service conditions in terms of mechanical and physical properties. Coating metal with good mechanical properties(usually steel) is often more practical in terms of cost and required life than selecting a more corrosion resistion but expensive material.Protection can be achieved in four ways, with many coatings functioning in more than one way:(1) A barrier coating that prevents the corrosive environment from contacting the metal.(2) A sacrificial coating that corrodes while giving cathodic protection to the underlying metal.(3) An inhibitor coating that slows electrode reactions.(4) An electrically resistive coating that stifles electrochemical corrosion cells, Paints fall into this last category.Corrosion InhibitorsAn inhibitor is a chemical added to the corrosive environment in small amounts to reduce the corrosion rate. Some inhibitors interfere with the anode reaction, some with the cathode reaction, and some with both. They usually used to prevent general corrosion but most are not effective in preventing localized attack, such as crevice corrosion, pitting, or stress-corrosion cracking. Inhibitors have a critical concentration that must be reached or exceeded for them to be effective, and in some cases to prevent them from making corrosion worse.Cathodic and Anodic ProtectionCathodic protection converts all anodic on a metal surface to cathodes so that corrosion ceases. The protected metal has positive current flowing onto it from the electrolyte everywhere on the surface so that no current flows off. This result can be achieved in two distinictly different ways.(1) By connecting a sacrificial anode the metal that is be protected.(2)By applying an electric current from a separate source, a technique called impressed-current cathodic protection.Anodic protection, on the contray, makes the entire metal surface anodic-so anodic that the metal completely passivates. Obviously, then, this technique is limited to metals that can form protective passive films. Since passivated metals still corrode at a low rate, anodic protection almost, but not completely, stops corrosion. Most corrosion problems originate with either improper design or improper material selection. However, a good choice of material can overcome severe environmental conditions and even some deficiencies in design.The methods listed above are the accepted ways of dealing with a corrosion problem, but not all of them apply in a given situation. In particular, the corrosion engineer often cannot change the service conditions or environment chemistry. These may be as unalterable as the ocean, or nearly as unalterable: an industrial process that is running fairly smoothly where any change will be fanatically opposed by the production people.阅读材料 10腐蚀控制腐蚀问题的解决方法如下：（1）选择抗腐蚀环境的材料；（2）给金属加一个保护层；（3）改变工作条件，如温度，压力或速度；（4）改变化学环境，如PH值，浓度，通风，杂质；（5）添加缓蚀剂；（6）改变金属阳极或阴极保护的电势；（7）完善设备或系统的设计；（8）让其腐蚀后取代它（通常是一个可行的替换物）。
过程装备与控制工程专业英语翻译
General Equilibrium Conditions of A System力系的一般平衡条件在这一部分，我们将研究为了使一个物体保持平衡，作用在其上的力和力偶所必须满足的条件。
根据牛顿第一定律，施加在一个静止物体上的力系的合力一定为零。
然而，请注意这个定律对力矩或力系的转动效应只字未提。
显然，合力矩也一定为零，否则物体将会转动。
这里的基本问题是原先叙述的牛顿第一定律（和第二定律）只适用于非常小的物体，或者尺寸可以忽略的非零质量的粒子。
然而，它可以扩展到如下所述的有限尺寸的物体。
考虑一个由两个质点组成的系统，假设1f 和2f 为它们之间的相互作用力(图.1.1)。
这些力称为内力，因为它们是由于系统内部的物体之间的相互作用而产生的。
假定内力服从牛顿第三定律，我们有12f f =-。
假如还有质点与系统外物体之间的相互作用力施加在质点上，如1,2F F 和3F ,这些力称为外力。
显然，作用在一个特定粒子上的力一定有相同的应用，因为粒子的尺寸可以忽略。
如果系统内的每一个质点处于平衡，我们就可以说系统是平衡的。
在本例中，依据牛顿第一定律，作用在每个质点上的力的合力一定为零。
对质点A 我们有：∑=++=0121f F F FA 而对质点B 有：∑032=+=F f F B作用在系统上的力的总和为：123120A B F F F F F F f f =+=++++=∑∑∑现在我们来研究这些力对于同一点P 的合力矩。
由图1.1，我们有：12()()P A B M r F r F =⨯+⨯∑∑∑ 由于力1f 和2f 有相同的作用线，力矩的条件可以改写为1121223()0P M r F F f f r F =⨯++++⨯=∑但12f f =-；所以力和力矩的条件简化为1210F F F F +=+=∑和111223()()()0P M r F r F r F =⨯+⨯+⨯=∑换句话说，如果系统处于平衡，那么作用在其上的合外力一定为零，而且这些力对于任一点的合力矩也为零。
过程装备与控制工程专业英语翻译
Unit 19 Types of Heat ExchangersHeat exchangers are equipment primarily for transferring heat between hot and cold have separate passages for the two streams and operate most versatile and widely used exchangers are the shell-and-tube types but various plate and other types are valuable and economically competitive or superior in some other types will be discussed briefly but most of the space following will be devoted to the shell-and-tube types primarily because of their importance but also because they are most completely documented in the they can be designed with a degree of confidence to fit into a other types are largely proprietary and for the most part must be process designed by their manufacturers.Plate-and-Frame Exchangers Plate-and-frame exchangers are assemblies of pressed corrugated plates on a frame. Gaskets in grooves around the periphery contain the fluids and direct the flows into and out of the spaces between the spacing and the presence of the corrugations result in high coefficients on both sides several times those of shell-andtube equipment and fouling factors are accessibility of the heat exchange surface for cleaning makes them particularly suitable for fouling services and where a high degree of sanitation is required as in food and pharmaceutical pressures and temperatures are limited by the natures of the available gasketing materials with usual maxima of 300 psig and 400 F.Since plate-and-frame exchangers are made by comparatively few concerns most process design information about them is proprietary but may be made available to serious factors and heat transfer coefficients vary with the plate spacing and the kinds of costs per unit of heat transfer are said to be lower than for shell-and-tube stainless steel construction the plate-and-frame construction cot is 50%-70% that of the shell-and-tube.Spiral Heat Exchangers In spiral heat exchangers the hot fluid enters at the center of the spiral element and flows to the periphery; flow of the cold liquid is countercurrent entering at the periphery and leaving at the transfer coefficients are high on both sides and there is no correction to the log mean temperature difference because of the true countercurrent'action. These factors may lead to surface requirements 20% or so less than those of shell-and-tube exchangers. Spiral types generally may be superior with highly viscous fluids at moderate pressures.Compact (Plate-Fin) Exchangers Compact exchangers are used primarily for gas they have surfaces of the order of 1200 m2 /m3 corrugation height mm corrugation thickness mm and fin density 230-700 fins/ large extended surface permits about four times the heat transfer rate per unit volume that can be achieved with shell-and-tube have beendesigned for pressiIres up to 80 atm or close spacings militate against fouling compact exchangers are used in cryogenic services and also for heat recovery at high temperatures in connection with gas mobile units as in motor vehicles compact exchangers have the great merits of compactness and light kind of arrangement of cross and countercurrent flows is feasible and three or more different streams can be accommodated in the same drop heat transfer relations and other aspects of design are well documented.Air Coolers In such equipment the process fluid flows through finned tubes and cooling air is blown across them with fans. The economics of application of air coolers favors services that allow 25-40 1" temperature difference between ambient air and process the range above 10 Mbtu/l air coolers can be economically competítíve with watercoolers when water of adequate quality is available in su Hicient amountDouble-Pipe Exchangers This kind of exchanger consísts of a central pipe supported withín a larger one by packíng glands. The straight length is limited to a maximum of about 20 ft;otherwise the center pipe wi1l sag and cause poor distribution in the is customary to operate with the high pressure high temperature high density and corrosive fluid in the inner pipe and the less demanding one in the annulus. The inner surface can be provide with scrapers as in dewaxing of oils or crystallization from longitudinal fins in the annular space can be used to improve heat transfer with gases or viscous greater heat transfer surfaces are needed several double-pipes can be stacked in any combination of series or parallel.Double-pipe exchangers have largely lost out to shell-and-tube units in recent may be worth considering in these situations:1. When the shell-side coefficient is less than half that of the tubeside;the annular side coeHicient can be made comparable to the tube side.2. Temperature crosses that require multishell shell-and-tube units can be avoided by the inherent true countercurrent flow in double pipes.3. High pressures can be accommodated more economically in the annulus than they can in a larger diameter shell.4. At duties requiring only 100~200 sqft of surface the double-pipe may be more economical even in comparison with off-the-shell unts.Shell-and-Tube Exchangers This type of exchangers will be discussed in the following section.(Selected from: Stanley Chemical Process Equiment Butterworth Publishers 1988.)Words and Expressionsn.通道，通过a.多用途的，通用的a.专利的，私有的v.成波纹状，起波纹;corrugation nn.沟，槽n.系数n.密封垫片v.弄脏，堵塞;fouling factor 污垢系数n.卫生a.制药的；药物的n. ; a.逆流n.翅片;v.装翅片v.妨碍，起作用a.冷冻的，低温的n.恢复，回收，再生n.填料盖，密封套v.下垂，下沉n.环状空间; annular a环形的.v.脱蜡n.结晶，结晶体n.堆积，烟囱α.内在的，固有的v.调节，适度，容纳Unit 19 换热器的种类换热器起初是为了在热流和冷流中传热。
过程装备与控制工程专业英语翻译
1、In our comparison of the net electrical power output of both combined heat and power (CHP)and power-only plants, the electrical output of the CHP plants is assumed to be the output that could the oretically be produced if there were no heat output.net electrical power 净电力combined heat and power 热电联供Plant 设备be assumed to be 假设为Theoretically 理论地；理论上在我们的热电联供和只供电的设备的净电力输出比较中，热电联供设备的电力输出是看做理论上如果没有热输出时产生的输出量。
2、The lower heating value is defined here as the higher heating value (HHV) minus the energy necessary to evaporate the water that is created by the combustion of the hydrogen in the fuel and minus the energy needed to evaporate the moisture that was already part of the fuel before combustion.heating value 热值Evaporate [ɪ'væpəret]vt. 使……蒸发；使……脱水；使……消失vi. 蒸发，挥发；消失，失踪Combustion [kəm'bʌstʃən] n. 燃烧，氧化；骚动moisture ['mɒɪstʃə] n. 水分；湿度；潮湿；降雨量低热值在这里定义为高热值减去使水分蒸发所需要的能量，这些能量包括使燃料中的氢燃烧产生的水分蒸发所必需的能量和使燃料燃烧前所含有的水分蒸发所需要的能量。
过程装备与控制工程专业英语翻译13
Reading Material 13Principles of Mass Transfer1. General RemarksSome of the most typical chemical engineering problems lie in the field of mass transfer. A distinguishing mark of chemical engineer is his ability to design and operate equipment in products is prepared, chemical reactions take place, and separations of the resulting products are made. This ability rests largely on a proficiency in the science of mass transfer. Applications of the principles of momentum and heat transfer are common in many branches of engineering, but the application of mass transfer has traditionally been largely limited to chemical engineering. Other important applications occur in metallurgical processes, in problems of high-speed flight, and in waste treatment and pollution-control processes. Eddy diffusion is apparent in thedissipation of smoke from a smokestack. Turbulence causes mixing and transfer of the smoke to the surrounding atmosphere. In certain locations where atmospheric turbulence is lacking, smoke originating at the surface of the earth is dissipated largely by molecular diffusion. This cause serious pollution problems because mass is transferred less rapidly by molecular diffusion than by eddy diffusion.4. Convective Mass-Transfer CoefficientsIn the study of heat transfer we found that the solution of the differential energy balance was sometimes cumbersome or impossible, and it was convenient to express the rate of heat flow in terms of a convective heat-transfer coefficient by an equation like )(m s t t h A q -=The analogous situation in mass transfer is handled by an equation of form)(Am As P A k N ρρ-=The mass flux N A is measured relative to a set of axes fixed in place. The driving force is the difference between the conversation at the phase boundary (a solid surface or a fluid interface) and the concentration at some arbitrarily defined point in the fluid medium. The convective coefficient P k may apply to forced or natural converction; there are no mass-transfer counterparts for boiling, condensation, or radiation heat-transfer coefficients,the value of P k is a function of the geometry of the system and the velocity and properties of the fluid, just as was the coefficient h .3. Eddy DiffusionJust as momentum and energy can be transferred by the motion of finite parcels of fluid, so mass can be transferred. We have seen that the rate of these transfer operations, caused by bulk mixing in a fluid, can be expressed in terms of the eddy kinematics viscosity, the eddy thermal diffusivity, and the eddy diffusivity. This latter quantity can be related to a mixing length which is the same as that defined in connection with momentum and energy transfer. In fact, the analogy between heat and mass transfer is so straightforward that equations developed for the former are often found to apply to the latter by a mere change in the meaning of the symbols.Molecular diffusion also occurs in liquids and solids. Crystals in an unsaturated solution dissolve,with subsequent diffusion away from the solid-liquid interface. Diffusion in solids is of importance in metallurgical operations. When iron which is unsaturated with respect to carbon is heated in a bed of coke, the concentration of the carbon near the surface is increased by inward diffusion of carbon atoms.The above remarks apply only in an approximate and qualitative way. The quantitative prediction of the diffusivity, thermal conductivity, and viscosity of a gas from a knowledge of molecular properties can be quite complicated. The consideration of such relations forms an important part of the subject of statistical mechanics.2. Molecular DiffusionMolecular diffusion occurs in a gas as a result of the random motion of the molecules. This motion is sometimes referred to as a random walk. Across a plane normal to the direction of the concentration gradient (or any other plane), there are fluxes of molecule in both directions. The direction of movement for any one molecule is independent of the concentration in dilute solutions. Consequently, in a system in which there is a concentration gradient, the fraction of molecules of a particular species (referred to as species A) which will move across a plane normal to the gradient is the same for both the high-and low- concentration sides of the plane. Because the total number of molecules of A on the high-concentration side is greater than on the low-concentration side, there is therefore a net movement of A in the direction in which the concentration of A is lower. If there are no counteracting effects, the concentrations throughout the mixture tend to become the same. In the analogous transfer of heat in a gas by conduction, the distribution of hotter molecules (those which have a higher degree of random molecular motion) tends to be evened out by random mixing on a molecular scale. Similarly, if there is a gradient of directed velocity (as distinguished from random velocity) across the plane, the velocity distribution tends toward uniformity as a result of the random molecular mixing. There is a transfer of momentum, which is proportional to the viscosity of the gas.In discussing the fundamentals of mass transfer we shall consider mainly binary mixtures, although multicomponent mixtures are important in industrial applications. Some of these more complicated situations will be discussed after the basic principles have been illustrated in terms of binary mixtures.The analogy between momentum and energy transfer has already been studied in some detail, and it is now possible to extend the analogy to include mass transfer.By mass transfer is meant the tendency of a component in a mixture to travel from a region of high concentration to one of low concentration. For example, if an open test tube with some water in the bottom is placed in a room in which the air is relatively dry, water vapor will diffuse out through the column of air in the test tube. There is a mass transfer of water from a place whereits concentration is high(just above the liquid surface) to a place where its concentration is low (at the outlet of the tube).If the gas mixture in the tube is stagnant, the transfer occurs by molecular diffusion. If there is a bulk mixing of the layers of gas in the tube by mechanical stirring or because of a density gradient, mass transfer occurs primarily by the mechanism of forced or natural convection. These mechanisms are analogous to the transfer of heat by conduction and by convection; there is, however, no counterpart in mass transfer for thermal radiation.阅读材料13传质原理1. 概述一些最典型的化学工程问题存在于质量转移领域。
过程装备与控制工程专业外语(原文+翻译)
Unit 21Pumps1. IntroductionPump, device used to raise, transfer, or compress liquids and gases. Four' general classes of pumps for liquids are described below t In all of them , steps are taken to prevent cavitation (the formation of a vacuull1), which would reduce the flow and damage the structure of the pump, - pumps used for gases and vapors are usually known as compressors . The study of fluids in motion is called fluid dynamics.1．介绍泵是提出，转移或压缩液体和气体的设备。
下面介绍四种类型的泵。
在所有的这些中，我们一步步采取措施防止气蚀，气蚀将减少流量并且破坏泵的结构。
用来处理气体和蒸汽的泵称为压缩机，研究流体的运动的科学成为流体动力学。
Water Pump, device lor moving water from one location to another, using tubes or other machinery. Water pumps operate under pressures ranging from a fraction of a pound to more than 10,000 pounds per square inch. Everyday examples of water pumps range from small electric pumps that circulate and aerate water in aquariums and fountains to sump pumps that remove 'Water from beneath the foundations of homes.水泵是用管子或其他机械把水从一个地方传到另一个地方。
过程装备与控制工程专业英语翻译4
Reading Material 4Stresses in Cylindrical Shells due to Internal PressureThe classic equation for determining stress in a thin cylindrical shell subjected to pressure is obtained from Fig.1.16. Summation of forces perpendicular to plane ABCD gives: PL ．2r =2σθLt or σθ=tr PWhere P=pressure, L=length of cylinder ,σθ=hoop stress ,r=radius, t=thicknessThe strain εθis defined asεθ=rrW r ππ2)(2+_rrrr ππ22 or εθ=rWAlso εr =drdWThe radial deflection of a cylindrical shell subjected to internal pressure is obtained by substituting the quantity into Eq.(1.18). Hence for thin cylinders W=Etr 2PWhere W= radial deflection, E= modulus of elasticityEquations (1.17) and (1.20) give accurate results when r >0. As t r decreases,however , a more accurate expression is needed because the stress distribution through the thickness is not uniform. Recourse is then made to the "thick shell" theory first developed by Lame. The derived equations are based on the forces and stresses shown in Fig.1.18.The theory assumes that all shearing stresses are zero due to symmetry and a plane that is normal to the longitudinal axes before pressure is applied remains plane pressurization. In other words ,ɛ1 is constant at any cross sectionA relationship between σrand σθcan be obtained by taking a free-body diagram ofring dr as shown in Fig.118b. Summing forces in the vertical direction and neglecting higher-orde terms ,we then have σθ—σr =drd rσA second relationship is written as σθ=μ）μ）（（211E-+[εθ(1-μ) +μ（εr+ε1）]σr =μ）μ）（（211E-+ [εr(1-μ)+μ（εθ+ε1）] σ1=μ）μ）（（211E-+ [ε1(1-μ)+μ（εθ+εr）]Substituting Eqs.(1.18) and (1.19) into the first two expressions of Eq.(1.22) and substituting the result into Eq.(1.21) results in:22drw d +r 1drdw —2rw =0A solution of this equation is W=Ar+rBWhere A and B are constants of integration and are determined by first substituting Eq.(1.23) into the first one of Eq.(1.22) and applying the boundary conditionsσr= —p i at r=r i at σr= —p o at r=r oExpression (1.23) then becomes: w= — μr ε1+)(122i O r r Er -［r 2(1-μ-2μ2)（P i r 2i -P O r 2O ）+r 2i r 2O (1+μ)（P i -P O ）］Once w is obtained, the values of σθare determined from Eqs.(1.18) ,and , (1.19) ,and (1.22)and expressed for thick cylinders asσθ=2222222))((iO Oi O i i O i i r r rr r P P r P r P --+-σr= —2222222))((P iO Oi O i i i i O r r rr r P P r r P --+-wh σr=radial stress σθ=hoop stress P i =internal pressure P O =externalpressurer i =inside radius r O =outside radius r=radius at any pointThe longitudinal stress in a thick cylinder is obtained by substituting Eqs.(1.18),(1.19),and (1.24)into the last expression of Eqs.(1.22) to give σ1=E ε1+2222i P (2iOO O i r rr P r --）μThis equation indicates that σ1 is constant throughout a cross section because ε1is constantand r does not appear in the second term. Thus the expression σ1 can be obtained from statics Asσ1=2222P iOOO i i r rr P r --With σ1 known, Eq.(1.24) for the deflection of a cylinder can be expressed as w=)()1()()21)((2222222i O O i O i O O i i r r Er r r P P r P r P r -+-+--μμ阅读材料 4圆柱壳体的应力源于内部压力圆柱形薄壳体源于内部压力的经典应力决定方程式可以从图1.16中得出。
过程装备与控制工程专业英语翻译 重点文章
Unit 5 Mechanical VibrationsA mechanical vibration is an oscillatory，periodically repeated motion of a particle or body about a position of equilibrium .An engineer is frequently confronted with the problem of machinery and structures.机械振动是质点或物体在其平衡位置附近所作的震荡的，周期性的往复运动。
工程师经常面临机械振动的问题，因为在某种程度上他们在几乎所有的机械和结构中遇到过这些问题Most vibrations are undesirable in machines and structures because they produce excessive stresses or repeated stresses;大多数的震动在机械和结构中是不希望存在的，因为震动会产生附加应力或者交变应力。
cause added wear;increase bearing loads; induce fatigue;create acute passenger discomfort in planes，ships，trains，buses，and automobiles;and absorb energy that could otherwise do useful work.引起额外磨损，增大轴承载荷，导致疲劳破坏，使飞机、船、火车及汽车上的乘客产生严重的不舒服感，并且振动会吸收本可以做有用功的能量。
The collapse of the Tacoma Narrows Bridge in 1940 is an example of structural failure due to excessive stresses produced by vibrations.The accuracy of precision instruments，tools，and machines may be impaired by excessive vibrations.1940年（发生的）塔克马窄桥的垮塌事件就是一个因为震动产生的附加应力导致结构失效的例子。
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PART Ⅲ工业流程Unit 11 化学工程1. 什么是化学工程？从广义上讲，工程被定义为特定行业使用的科学技术和设施，例如，机械工程是指技术和设施被用来制造及其，它（机械工程）主要是以机械力基础，这些力用于改变被加工材料的表面形状或物理性质，而材料的化学性质不变。
化学工程包括材料的化学加工，主要以化学和物理化学的高度复杂性为基础。
因此，化学工程是注重设计，制造，机械设备操作，化学加工工业机械等要就工程领域的分支。
化学工业是首先以化学科学为基础，例如物理化学，化学热力学，和化学动力学。
等等，然而，它（化学工程）不是简单的复制他们的发现，而是依靠他们进行大量的化学处理。
主要的目的是使化学工程成为一门纯粹的学科，是一种能够找到一种操作和设计商业设备及配件最适合最经济的方案。
因此，化学工程在没有经济，物理，数学，控制理论，机械原理，和其他科学技术的紧密联系是不可想象的。
在化学工程的早期，化学工程是一门大的描述性的学科。
在那时许多的早期的化学工程的教科书和手册都是百科全书一样商业生产过程中所知道。
在科学和工业制造取得进展并在增加化学制品的数量上给人印象深刻。
如今，是有充当的80，000种化学品的生产来源。
化学工业的发展，一方面使化学和技术科学向前发展，另一方面可为化学加工工艺奠定理论基础。
随着化学工程的稳步向前发展，新的数据，新的联系，新的归纳正在被加入化学工程的主题。
许多他们自己的分支区别化学工程的主流。
正如加工和机械设计，自动化，化学模拟加工和建模等等。
2. 化学工程的基本趋势？化学工程一直被用来加工工业来改变原料的物理状态或化学成分。
化学工程师所研究问题的传统范围，从复杂性和规模上来讲，也许都可以称之为是中等尺度的问题。
这种尺度包含反应器和单一工序的装备以及制造工厂里单位操作的组合体。
未来的中等尺度研究将越来越多地有微观尺度的研究和极端复杂系统的宏观尺度的研究来补充。
化学工程将来会整合成比其他任何工程领域分支都宽尺度（的工程学科）。
例如，一些工作可能把宏观尺度的环境和中间尺度的燃烧系统和微观尺度的分子反应和运动联系起来。
另一些工作可能把一个复合的飞行器的宏观尺度的性能和中间尺度的机翼的化学反应器以及反应器的布局将受复杂液体的微观动力学研究的影响。
如此，将来化学工程将会构想和在微观到宏观的连续的尺度范围内严谨的解决问题。
他们将会新的工具和新的观察发现以及研究其他学科：分子生物学，化学，固体物理，材料科学，和电子工程。
并且他们在制造和过程设计和加工方面将会越来越多的用计算机，人们的智慧，以及解决问题的专门的系统。
Unit 12 工业制造的传递现象1. 引言传递现象是一个共有的名词来源于有规则的集成研究的三个古典的工程领域的学科；（1）能量或热传动，（2）质量传递或扩散（3）动量传递或流体动力学。
当然，热和质量传递发生在流体中，正是由于这个原因一些工程研究人员们青睐于热传导和固体扩散，然而，这个学科实际上是比流体力学的范围更广。
该学科不同于流体力学之处还在于传递现象的研究利用了传热，传质，和动量传递方程之间的相似性。
这些相似性，随着它们经常被提起，能够经常涉及到相似的物理构造借以发生传送，因而，明白一个传送过程就可以明白另一个传送过程。
而且，如果微分方程和边界条件都相同，则仅需对其中一个（传递）过程求解，因为通过改变名称，该解可用作任何其他传递过程的解。
需要强调的是，然而，在传递过程中有很多相似之处，也有很重要的不同之处，尤其在动量传动，和热或质量传递。
尽管如此，一个对传递过程相似之处有系统的研究会使识别和明白他们的不同之处变得更加简单。
2. 为什么工程师要研究传递现象？自从这门学科涉及到一些自然规律，一些人把它归类为工程方面的一个分支。
这如这些原因一些参与经济性设计和设备操作以及技能方面的工程师，十分适当地提出传递现象将会在实践中体现价值。
大致有两种答案回答这些问题。
第一种要要求认识热，质量，动量等传递发生在各种工程设备中，热交换器，压缩机，核电站，增湿机，空气冷却器，干燥器，分馏器，减震器等等。
这些传递过程也参与到人体当中就像在复杂得过程凭借污染物质的其反应扩散到大气中。
如果工程师想要了解在工程装备中所发生的情况，并就造作的经济性做出明智的决策，那么他们应该对控制这些传递过程的物理定律有所理解，这一点很重要。
第二中答案是工程师们需要能够用他们对自然规律的理解来设计这些正在发生的装备过程。
这样做他们必须预测出热，质量或动量等传递的比率。
例如，考察一个简单的换热器，即一根管子，通过保持器壁温高于流过管内的流体温度，即可加热流体。
这个比率通过管壁传热给流体的依靠的因素叫做热传递系数这是在进行昂贵的实验室或试验工厂测量后以及通过相关度量的以观察或实验为依据的方程式所获得的。
这些方程式在一定范围内适合一些数据的方程式；它们不是建立在原理的基础上，也不能用在已经获得数据的精确度意外的问题上。
更便宜的而且一般更可靠的方程式被用在传递现象来预测传热系数通过以自然规律为基础的方程式。
这些预测的结果将会通过一个研究工程师计算一些方程式（通常是用计算机）后获得的。
一个设计工程师将会用这些方程式是研究型的工程师获得传热系数。
记住设计热交换器的工作一样也是不管如何要先得到传热系数。
由于这个原因，一些传递现象的课程仅仅强调传热系数的确定和实际的单元操作课程的设计水平。
当然获得参数也是很重要的，热传递系数被用作设计，也正是由于这些原因一个传递课程可以被认为是一个工程课程就像是一门学科。
事实上，有一些设计的工程师可以用这个方法和传递想象的方程式直接用于设备的设计的例子。
一个例子就是一个作为一个管子说明的管子型的反应器，这个热交换器伴随着均相化学反应发生在里面会描述的早些，流体以某种反应物浓度进入管子，而以减小了的反应物浓度和提高了的产品浓度排除管子。
当然，不是所有的问题今天都可以用这种方式解决。
然而，随着计算机的发展，越来越多的问题将会用这种方法解决。
如果工程学的学生接受教育没有变得过时，那他们必须做好思想准备，同伙理解传递现象的一种方法，应用计算机将会创造未来。
因为它有巨大的潜力正像他的应用的趋势，传递现象的课程将会最终证明这是在大学生涯最实际而且有用的的课程。
Unit 13传热原理实际的全部的已完成的操作都有化学工程参与生产或以热的形式吸收能量。
因此，控制传热的定律和以控制热流为主要目的的仪器类型都是很重要的。
1.自然的热流动当两个不同温度的物体进行接触时，热量会有温度高的物体流到温度地的物体。
这种流动经常朝着温度下降的方向，热的流动有三种途径：传导，对流，和辐射。
传导如果一个连续的实体中存在着温度变化，热量可能流动不伴随物质的任何运动。
热量的这种流动叫做传导。
在金属体中，热传递的结果来自自由电子的运动，所以热传递和电的传导率很相似。
在电的传导率低的实体中，在大多数的液体中，热传导的结果伴随着温度变化的分子运动的动量。
气体的传导发生在任意的运动的分子，所以热是一种扩散从高温地区传导低温地区。
区普通的传导的例子就是热在不透明的物体中流动，就像火炉里的砖墙或是管子的金属壁。
对流当一个宏观的液体微粒穿过一个特定的表面，例如一个固定容积的范围内，它带有确定数目的焓。
这样的焓的流动来自连续的热的流动或者简单的对流。
由于对流是一种宏观现象，因此，只有当力作用在微团或液流上且该力能够克服摩擦力并维持其运动时，这种传递现象才能发生。
对流的一个例子是焓的变化由于湍流流动和由于热的空气流过普通的冷却器。
自然和强制对流强制对流在液体中有两种形式，如果这种趋势的原因是密度不同和液体中温度变化引起的密度不同所产生的浮力。
这个作用叫做自然对流。
流动的空气穿过加热的冷却器就是自然对流的一个例子。
如果这个气流产生的运动被机械力的作用分开如泵和搅拌器，这种流动域密度的变化程度无关叫做强制对流。
热流动由液体被泵入以个加热的管子就是强制对流的例子。
这两种力有可能同时在同一种液体中作用，这是自然对流和强制对流共同作用。
辐射辐射是一个术语来自于能量以电磁波的形式穿过空间，如果辐射正在穿过空的空间，它不会改变热或其它任何形式的能量。
也不会使它偏离原来的路径。
然而。
在它自己的路径中，辐射将会被传播，被反射或者被吸收。
它仅通过吸收能量来产生热量，这种改变是数量上的，例如，融化的石英传播所有的辐射当它受到打击是；一个磨亮的不透明的表面将会吸收大多数的辐射，并将会改变这样吸收能量数量上的在热中。
单元子和双原子气体对热射线是可以通过的，经常发现热经过某种气体团是，它可以通过辐射的方式也可以传导。
例子是；从散热器或未保温的蒸汽管道向周围环境气体损失热量在熔炉传热以及其它高温气体加热损失。
这两个机制是互相独立并且是并行产生的。
所以一种类型的热流动可以被控制或与其它独立的。
传热，对流和辐射都被分开和避免相互间造成影响二者都很重要。
在一般的条件下，射线变得重要并与液体流动的情况无关。
传热传导它们对流动状态是非常敏感的收温度影响的。
2.传热率热通量传热计算是基于热的传热表面的面积用平方英尺每小时的单位表示。
每单位面积的传热率叫做热通量。
许多类型的传热装备都是用管子构成的。
热通量也可以在内表面上，或者在管子的外表面。
尽管这个选择是随意的，但它必须得明确的规定因为热通量的重要的数值是不同的。
流体流动的平均温度当一个流体正在变热或者变冷时，流体横截面的温度会变化。
如果流体被加热，流体靠近加热表面的温度最高，中心外温度逐渐降低，如果流体被冷却，流体靠近冷却表面的温度最低，从中心到表面温度组件升高。
应为这个温度变化遍及整个流体的横截面。
为了明确，我们必须指出，流体的温度是指什么。
大家一致认为，流束的温度就是假设把流过所研究截面的全部流束取出并绝热混合后所达到的均匀温度。
这个温度所以明确的叫做平均或流体混合温度。
Unit 14化学工程的单元操作1.介绍化学加工可以包含各种各样的不同的过程顺序，它的原理是独立于我们的操作的材料和操作的系统，把复杂的工艺过程分解成单个的物理过程（即单元操作）和多种化学反应过程的实践，导致了化学工程的通用性。
单元操作的观念在化学工程是基于不同的过程步骤可以减少简单操作或反应，而这些反应在不考虑操作条件下有同样的基本反应。
这个原则，在美国化学工业的发展过程中变得明显，在1915年早些首次变得明显。
任何一个化学过程，无论所操作规模大小，可以被分解成单元作用的同等的一些系列，像粉碎，混合，加热，烘干，吸取，浓缩，析出，沉淀，结晶，过滤，溶解，电解等等。
基本单元操作的数量不是很大而且只有很少几个包含特定的操作，化学工程的复杂性源于各种条件如温度，压力等的多样性。
由于条件的变化，单元作用就必须在不同的过程中完成。
同时化学工程的复杂性还受到由反应物的物理及化学性质所决定的结构材料和设备设计的影响。