建筑环境与设备工程专业英语翻译.pdf

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1、A thermodynamic system is a region in space or a quantity of matter bounded by a closedA thermodynamic system is a region in space or a quantity of matter bounded by a closedsurface.surface. TheThe surroundingssurroundings includeinclude everythingeverything externalexternal toto thethe system,syste

2、m, andand thethe systemsystem is isseparatedseparated fromfrom thethe surroundingssurroundings byby thethe systemsystem boundaries.boundaries. TheseThese boundariesboundaries cancan bebemovable or fixed, real or imaginary.movable or fixed, real or imaginary.一个热力学系统是一个在空间或有事项的数量由一个封闭的表面范围内的区域。周围环境包括一

3、切外部系统，系统是从周围环境隔开的系统边界。这些边界可以是动产或固定的，真实的或想象。The concepts that operate in any thermodynamic system are entropy and energy. EntropyThe concepts that operate in any thermodynamic system are entropy and energy. Entropymeasuresmeasures thethe molecularmolecular disorderdisorder ofof a a system.system. The

4、The moremore mixedmixed a a system,system, thethe greatergreater itsitsentropy; conversely, an orderly or unmixed configuration is one of low entropy. Energy hasentropy; conversely, an orderly or unmixed configuration is one of low entropy. Energy hasthe capacity for producing an effect and can be c

5、ategorized into either stored or transientthe capacity for producing an effect and can be categorized into either stored or transientforms as described in the following sections.forms as described in the following sections.熵和能量的概念，在任何热力学系统操作。熵措施分子系统紊乱。更为复杂的系统，其熵值越大，反之，有序或纯配置是低熵之一。能源已经产生效果的能力，并在下面的章节

6、中所述，可以存储或短暂形式分类。HeatHeat Q Q is is thethe mechanismmechanism thatthat transferstransfers energyenergy acrossacross thethe boundariesboundaries ofof systemssystems withwithdiffering temperatures, always toward the lower temperature. Heat is positive when energydiffering temperatures, always toward th

7、e lower temperature. Heat is positive when energyis added to the system.is added to the system.WorkWorkis is thethe mechanismmechanism thatthat transferstransfers energyenergy acrossacross thethe boundariesboundaries ofof systemssystems withwithdifferingdiffering pressurespressures (or(or forceforce

8、 ofof anyany kind),kind), alwaysalways towardtoward thethe lowerlower pressure.pressure. If If thethe totaltotaleffecteffect producedproduced inin thethe systemsystem cancan bebe reducedreduced toto the raisingthe raising ofof a weight,a weight, then nothingthen nothing butbutwork has crossed the bo

9、undary. Work is positive when energy is removed from the system.work has crossed the boundary. Work is positive when energy is removed from the system.热量 Q 与不同的温度，跨系统的边界传输能量总是向温度较低的机制。热是积极的，当能量被添加到系统中。功是指通过存在压差（任一种力）的系统边界传递能量的作用过程，总是指向低压， 如果系统中产生的总效果能被简化为一个重物的提升，那么只有功通过了边界，当能量从系统中一出时，功是正的。A property

10、 of a system is any observable characteristic of the system. The state of a system isA property of a system is any observable characteristic of the system. The state of a system isdefineddefined byby listinglisting itsits properties.properties. TheThe mostmost commoncommon thermodynamicthermodynamic

11、 propertiesproperties arearetemperature T, pressure p, and specific volume v or densitytemperature T, pressure p, and specific volume v or density. Additional thermodynamic. Additional thermodynamicproperties include entropy, stored forms of energy, and enthalpy.properties include entropy, stored fo

12、rms of energy, and enthalpy.Frequently,Frequently, thermodynamicthermodynamic propertiesproperties combinecombine toto formform otherother properties.properties.Enthalpy h, a result of combining properties, is defined as:Enthalpy h, a result of combining properties, is defined as:h=u+pvh=u+pvwhere u

13、 is the internal energy per unit masswhere u is the internal energy per unit mass系统属性是系统的任何观察到的特征。系统状态的定义是通过列出其属性。最常见的热力学性质的温度 T，压力P，和特定的体积V 或密度。其他热力学性质包括熵，能量储存形式，和焓。通常情况下，热力学性质相结合，形成其他属性。焓 H，一个属性相结合的结果，被定义为：H = U + PV其中 u 是每单位质量的内部能量Each property in a given state has only one definite value, and an

14、y property always has theEach property in a given state has only one definite value, and any property always has thesame value for a given state, regardless of how the substance arrived at that state.same value for a given state, regardless of how the substance arrived at that state.A A processproce

15、ss is is a a changechange inin statestate thatthat cancan bebe defineddefined asas anyany changechange inin thetheproperties of a system. A process is described by specifying the initial and final equilibriumproperties of a system. A process is described by specifying the initial and final equilibri

16、umstates,states, thethe pathpath (if(if identifiable),identifiable), andand thethe interactionsinteractions thatthat taketake placeplace acrossacross systemsystemboundaries during the process.boundaries during the process.中的每一个给定的状态的属性只有一个定值， 和任何财产总是有相同的值给定的状态，不管如何抵达该国的物质。一个进程是一个状态的改变，在系统属性的任何改变，可作为

17、定义。一个过程是指定的初始和最终的平衡状态，路径（如果识别），并采取跨系统的边界，在这个过程中发生的相互作用。A cycle is a process or a series of processes wherein the initial and final states of the systemA cycle is a process or a series of processes wherein the initial and final states of the systemare identical. Therefore, at the conclusion of a cycl

18、e, all the properties have the same valueare identical. Therefore, at the conclusion of a cycle, all the properties have the same valuethey had at the beginning.they had at the beginning.A pureA pure substance hassubstance has a a homogeneous andhomogeneous and invariableinvariable chemicalchemical

19、position. It It cancanexist in more than one phase, but the chemical composition is the same in all phasesexist in more than one phase, but the chemical composition is the same in all phases一个周期进程的一个过程或一个系列，其中系统的初始和最终状态是相同的的。因此，在一个周期结束时，所有属性具有相同的价值，他们开始。纯物质均匀的和不变的化学成分。它可以存在于超过一个阶段，但在各个阶段的化学成分是一样的If

20、a substance is liquid at the saturation temperature and pressure, it is called a saturatedIf a substance is liquid at the saturation temperature and pressure, it is called a saturatedliquid.liquid. If If thethe temperaturetemperature ofof thethe liquidliquid is is lowerlower thanthan thethe saturati

21、onsaturation temperaturetemperature forfor thetheexistingexisting pressure,pressure, it it is is calledcalled eithereither a a subcooledsubcooled liquidliquid (the(the temperaturetemperature is is lowerlower thanthan thethesaturationsaturation temperaturetemperature forfor thethe givengiven pressure

22、)pressure) oror a a compressedcompressed liquidliquid (the(the pressurepressure is isgreater than the saturation pressure for the given temperature).greater than the saturation pressure for the given temperature).如果一种物质在饱和温度和压力的液体，它被称为饱和液体。如果液体的温度低于现有的压力的饱和温度， 它被称为是过冷液体 （温度低于给定压力的饱和温度）或压缩液体（压力大于饱和为给

23、定的温度压力）。If If a a substancesubstance existsexists asas a a vaporvapor atat saturationsaturation temperaturetemperature andand pressure,pressure, it it is is calledcalled a asaturatedsaturated vapor.vapor. WhenWhen thethe vaporvapor is is atat a a temperaturetemperature greatergreater thanthan thethe

24、 saturationsaturationtemperature, it is a superheated vapor. Pressure and temperature of a superheated vapor aretemperature, it is a superheated vapor. Pressure and temperature of a superheated vapor areindependentindependent properties,properties, becausebecause thethe temperaturetemperature cancan

25、 increaseincrease whilewhile pressurepressure remainsremainsconstant.constant. GasesGases suchsuch asas airair atat roomroom temperaturetemperature andand pressurepressure areare highlyhighly superheatedsuperheatedvapors.vapors.如果一种物质在饱和温度和压力的蒸气存在，它被称为饱和蒸气。当蒸汽温度大于饱和温度，它是一个热蒸气。过热蒸汽压力和温度是独立的属性，因为温度增加，

26、而压力保持不变。如在常温常压下空气的气体是高度过热蒸汽。The second law of thermodynamics differentiates and quantifies processes that only proceedThe second law of thermodynamics differentiates and quantifies processes that only proceedin a certain direction (irreversible) from those that are reversible. The second law may bei

27、n a certain direction (irreversible) from those that are reversible. The second law may bedescribed in several ways. One method uses the concept of entropy flow in an open systemdescribed in several ways. One method uses the concept of entropy flow in an open systemandand thethe irreversibilityirrev

28、ersibility associatedassociated withwith thethe process.process. TheThe conceptconcept ofof irreversibilityirreversibility providesprovidesadded insight into the operation of cycles.added insight into the operation of cycles.热力学第二定律的区别和量化，只有在某一个方向，是可逆的（不可逆）进行的过程。第二定律可能在几个方面。一种方法是使用在一个开放的系统，并与进程关联的不可

29、逆性的熵流的概念。不可逆转的概念到周期的运作提供额外的洞察力。The Carnot cycle, which is completely reversible, is a perfect model for a refrigeration cycleThe Carnot cycle, which is completely reversible, is a perfect model for a refrigeration cycleoperating between two fixed temperatures, or between two fluids at different temp

30、eraturesoperating between two fixed temperatures, or between two fluids at different temperaturesand each with infinite heat capacity. Reversible cycles have two important properties: (1) noand each with infinite heat capacity. Reversible cycles have two important properties: (1) norefrigerating cyc

31、le may have a coefficient of performance higher than that for a reversiblerefrigerating cycle may have a coefficient of performance higher than that for a reversiblecyclecycle operatedoperated betweenbetween thethe samesame temperaturetemperature limits,limits, andand (2)(2) allall reversiblereversi

32、ble cycles,cycles, whenwhenoperated between the same temperature limits, have the same coefficient of performanceoperated between the same temperature limits, have the same coefficient of performance卡诺循环，这是完全可逆的，是一个完美的模型之间的两个固定的温度，或在不同温度和热容量无限每个的两种流体之间的制冷循环的运行。 可逆循环有两个重要的属性：（1）无制冷循环的性能系数之间相同的温度限制经营的

33、可逆循环高于，（2）之间相同的温度极限运行时，所有可逆循环，同样的性能系数FlowingFlowing fluidsfluids inin heating,heating, ventilating,ventilating, air-conditioning,air-conditioning, andand refrigerationrefrigeration systemssystems cancantransfer heat, mass, and momentum. This chapter introduces the basics of fluid mechanicstransfer h

34、eat, mass, and momentum. This chapter introduces the basics of fluid mechanicsrelatedrelated toto HVHVACAC processes,processes, reviewsreviews pertinentpertinent flowflow processes,processes, andand presentspresents a a generalgeneraldiscussion of single-phase fluid flow analysis.discussion of singl

35、e-phase fluid flow analysis.流动的液体在加热，通风，空调和制冷系统，可以传递热量，质量和动量。本章介绍有关暖通空调过程的流体力学，评论相关的流程，基础知识，并提出了一种单相流体流动分析的一般性讨论。FluidsFluids differdiffer fromfrom solidssolids inin theirtheir reactionreaction toto shearing.shearing. WhenWhen placedplaced underunder shearshear stress,stress, a asolid deforms only a

36、 finite amount, whereas a fluid deforms continuously for as long as thesolid deforms only a finite amount, whereas a fluid deforms continuously for as long as theshear is applied. Both liquids and gases are fluids. Although liquids and gases differ stronglyshear is applied. Both liquids and gases ar

37、e fluids. Although liquids and gases differ stronglyin the nature of molecular actions, their primary mechanicalin the nature of molecular actions, their primary mechanicaldifferences are in the degreedifferences are in the degreeof compressibility and liquid formation of a free surface. In general,

38、 liquids are consideredof compressibility and liquid formation of a free surface. In general, liquids are consideredincompressible fluids; gases may range from compressible to nearly incompressible.incompressible fluids; gases may range from compressible to nearly incompressible.流体与固体区别在于他们对剪切力的反应作用

39、。在施加剪切力时，固体只发生有限的变形， 而只要有剪切力的作用流体就会连续变形。流体不同于固体剪切他们的反应。当剪切应力下了坚实的变形量只有有限的，而流体的剪切变形。液体和气体都是流体。 虽然液体和气体的分子运动特性有着很大的区别，但是他们的主要的力学区别在于可压缩性的程度和液体自由表面 （界面） 的形成。 在一般来说，液体被认为是不可压缩的流体，气体可能范围从可压缩到几乎不可。Viscosity is a measure of a fluids resistance toViscosity is a measure of a fluids resistance to shear. Visco

40、us effects are taken into account shear. Viscous effects are taken into accountby categorizing a fluid as either Newtonian or non-Newtonian. In Newtonian fluids, the rateby categorizing a fluid as either Newtonian or non-Newtonian. In Newtonian fluids, the rateofof deformationdeformation is is direc

41、tlydirectly proportionalproportional toto thethe shearingshearing stress;stress; mostmost fluidsfluids inin thethe HVHVACACindustry (e.g., water, air, most refrigerants) can be treated as Newtonian. In non-Newtonianindustry (e.g., water, air, most refrigerants) can be treated as Newtonian. In non-Ne

42、wtonianfluids,fluids, thethe relationshiprelationship betweenbetween thethe raterate ofof deformationdeformation andand shearshear stressstress is is plicated.粘度是流体的抗剪切的措施。考虑采取分类流体为牛顿或非牛顿粘性的影响。在牛顿流体，变形率是成正比的剪应力;在暖通空调行业（如，水，空气，大部分制冷剂）牛顿流体可以作为治疗。在非牛顿流体，变形和剪切应力率之间的关系更为复杂。HeatHeatis is energyenergy inin

43、 transittransit duedue toto a a temperaturetemperature difference.difference. TheThe thermalthermal energyenergy is istransferredtransferred fromfrom oneone regionregion toto anotheranother byby threethree modesmodes ofof heatheat transfer:transfer: conduction,conduction,convection, and radiation. H

44、eat transfer is among a group of energy transport phenomenaconvection, and radiation. Heat transfer is among a group of energy transport phenomenathat includes mass transfer, momentum transfer or fluid friction and electrical conduction.that includes mass transfer, momentum transfer or fluid frictio

45、n and electrical conduction.热是由于温差在传输过程中的能量。 热能是从一个地区转移到另一个传热的三种模式：传导，对流和辐射。传热之间的能源运输的现象，其中包括传质，动量传递或流体摩擦和导电。ThermalThermal conductionconduction is is thethe mechanismmechanism ofof heatheat transfertransfer wherebywhereby energyenergy is is transportedtransportedbetween parts of continuum by the tr

46、ansfer of kinetic energy between particles or groups ofbetween parts of continuum by the transfer of kinetic energy between particles or groups ofparticles at the atomic level. In gases, conduction is caused by elastic collision of molecules;particles at the atomic level. In gases, conduction is cau

47、sed by elastic collision of molecules;inin liquidsliquids andand electrically nonconductingelectrically nonconducting solids,solids, it it is is believedbelieved toto bebe caused by longitudinalcaused by longitudinaloscillationsoscillations ofof thethe latticelattice structure.structure. ThermalTher

48、mal conductionconduction inin metalsmetals occurs,occurs, likelike electricalelectricalconduction,conduction, throughthrough thethe motionmotion ofof freefree electrons.electrons. ThermalThermal energyenergy transfertransfer occursoccurs inin thethedirectiondirection ofof decreasingdecreasing temper

49、ature.temperature. InIn solidsolid opaqueopaque bodies,bodies, thermalthermal conductionconduction is is thethesignificantsignificant heatheat transfertransfer mechanismmechanism becausebecause nono netnet materialmaterial flowsflows inin thethe processprocess andandradiation is not a factor.radiati

50、on is not a factor.热传导传热， 使能量是连续部分之间的运输粒子在原子水平上的颗粒或团体之间的动能转移的机制。气体中，分子的弹性碰撞引起的传导;电导电液体和固体，它被认为是造成晶格结构的纵向振荡。金属的热传导时，如导电，通过自由电子的运动。热能量转移发生在温度降低的方向。在坚实的不透明机构，热传导是显著的传热机制，因为没有净物资流动的过程中，辐射是不是一个因素。When fluid currents are produced by external sources (for example, a blower or pump), theWhen fluid currents