能源与动力工程专业英语

SpecializedEnglishforEnergyandPowerEngineering能源与动力工程专业英语Lecture1Introduction引言

1.1什么是专业英语

普通英语（CommonEnglish,OrdinaryEnglish）科技英语（EnglishforScienceandTechnology）专业英语（EnglishforSpecialScienceandTechnology）是结合各自专业的科技英语

有很强的专业性，涉及的面更加狭窄，与专业内容配合更为密切。隶属于科技英语是科技英语的一部分，以表达科技概念、理论与事实为主要目的。遵守科技英语的语法体系和翻译方法;特别注重客观事实和真理，表达准确、精练和正式。

专业英语与科技英语既有区别又有联系。专业英语的学习需要有一个良好的科技英语基础，同时也要注意其自身的词汇特点、语法特点、修辞特点和翻译特点等等。31.2学习专业英语的重要性(1)科研信息获取

(2)研究成果展示(3)国际交流合作

当前大部分资料都可以通过互联网传播，而这些资料中90％以上都是英语。世界上科技情报资料的交流主要靠使用英语,对子热能动力工程、制冷与空调等专业来说，绝大部分专业资料和信息都是以英语形式出现。专业英语阅读能力申报国家奖项申请专利发表学术论文：85％以上的科技资料都是以英语形式出版的专业英语写作能力专业英语表达、听说、应变能力4Lecture2FeaturesofSpecializedEnglish专业英语的特点2.1GrammarFeatures客观性（Objective）、准确性（accuracy）和精练性(conciseness)。(1)广泛使用被动语态(2)广泛使用非谓语形式(3)省略句使用频繁(4)It句型和祈使句使用频繁(5)复杂长句使用频繁(6)后置形容词短语作定语多语法特点6(1)广泛使用被动语态2.1GrammarFeatures主体多为客观的事物、现象和过程，在叙述推理过程中切忌加进作者个人的主观臆断；中心是客观现象及事物本身，而非动作的发出者，把论证说明的对象置于句子主语的位置，既能突出中心，又能吸引读者的注意。(客观性)1)Utilityboilersareusedprimarilytogenerateelectricityinlargecentralpowerstations.大型中心电站的电站锅炉主要用来发电2）Noworkcanbedonewithoutenergy没有能量不能做功。72.1GrammarFeatures3)Electricpowerisgeneratedinpowergeneratingstationsorplants.电能是在发电站或发电厂产生的4)Themetersarecalibratedandthescaleisdesignedtoreadthevalueofthedesiredunit.这些仪表可以被校准并且设计了不同的量程，以便读出期望的数值。82.1GrammarFeatures(2)广泛使用非谓语形式

非谓语动词在句子中可以起到名词，形容词或副词作用，动词的非谓语形式分为动名词,分词,动词不定式。①动名词

用动名词短语取代时间从句或简化时间陈述句Thesignalshouldbefilteredbeforeitisamplified.2)Anobjectbecomeshot.Itisplacedinthesun.Oncebeingplacedinthesun,anobjectbecomeshot.物体放置在太阳下会变热。

Thesignalshouldbefilteredbeforebeingamplified.放大信号前，应先对其进行滤波(精炼)92.1GrammarFeatures3)Wemustdovariousexperimentsbeforeanewair-conditioningproductisdesigned.Beforedesigninganewair-conditioningproductwemustdovariousexperiments.在设计一个新的空调产品之前，我们必须做各种实验用动名词短语做主语4)Changingresistanceisamethodforcontrollingtheflowofthecurrent.改变电阻是控制电流的一种方法5)Conductingelectricitymeanstheflowofelectronsthroughanobject.传导电流意味着电子在物体内的流动102.1GrammarFeatures②分词

过去分词短语替代从句中的被动语态

现在分词短语替代从句中的主动语态

Thepowersupply,whichisshowninblock-diagraminFig.1,isasingle-phaseinverter.Thepowersupplyshowninblock-diagraminFig.1isasingle-phaseinverter.图1中用框图表示的电源是一个单相逆变器。112.1GrammarFeatures2)Athermodynamicsystem,asitwaspointedoutabove,isafixedquantityofmattercontainedwithinsomeenclosure.Athermodynamicsystem,aspointedout

above,isafixedquantityofmattercontainedwithinsomeenclosure.

如上所述，热力系统是一包围在某一封闭边界内的具有固定质量的物质。3)Matterisanythinghavingweightandoccupyingspace.任何具有重量并占有空间的东西都是物质。122.1GrammarFeatures③不定式用不定式短语来替代表示目的和功能的从句或语句(1)Thecapacityofindividualgeneratorsislargerandlargersothattheincreasingdemandofelectricpowerissatisfied.Thecapacityofindividualgeneratorsislargerandlargertosatisfytheincreasingdemandofelectricpower.单台发电机的容量越来越大，目的就是满足不断增长的用电需求。(2)Whatdoesafusedo?Itprotectsacircuit.Thefunctionofafuseistoprotectacircuit.保险的作用就是保护电路。132.1GrammarFeatures(3)省略句使用频繁省略成分：状语从句中的主语、全部或部分谓语；定语从句中的关系代词which和that、从句中的助词等；还常用介词短语替代从句。1)If

itis

possible,theopen-loopcontrolapproachshouldbeusedinthissystem.Ifpossible,theopen-loopcontrolapproachshouldbeusedinthissystem.2)As

illustratedinFig.1,thereisafeedbackelementintheclosed-loopsystem.AsinFig.1,thereisafeedbackelementintheclosed-loopsystem.就像图1所示的那样，这个闭环系统中有一个反馈元件。可能的话，这个系统应该使用开环控制方法。(精炼)142.1GrammarFeaturesAsalreadydiscussed前已讨论Asexplainedbefore前已解释Asdescribedabove如上所示Ifpossible(necessary)如果可能（必要）其他常用的省略形式：Ifso倘若如此Aspreviouslymentioned前已提到Whenneeded(necessary,feasible)必要时Wherefeasible在实际可行的场合Wherepossible在可能的情况下152.1GrammarFeatures(4)It句型和祈使句使用频繁It句型：it充当形式主语，避免句子“头重脚轻”Itisveryimportant(possible,necessary,natural,inevitable)to…Ittakesverymuchtimelearning…Itisclear(possible,necessary,natural,inevitable)that…Ithappenedthat…Itmustbeadmittedthat…祈使句:无主语，精炼。LetAbeequaltoB.设A等于B。Considerahigh-pressurechamber.假如有一个高气压气候室。（准确、精炼）162.1GrammarFeatures(5)复杂长句使用频繁1)Inthedescriptionofaflowfield,itisconvenienttothinkofindividualparticleseachofwhichisconsideredtobeasmallmassoffluid,consistingofalargenumberofmolecules,thatoccupiesasmallvolumethatmoveswiththeflow.描述流场时，将着眼点放在流体独立质点上是非常方便的。每个质点都包含了微小质量的流体，它由大量分子组成。质点占据很小的体积，并随流体流动而移动。（准确、精炼）为了完整、准确地表达事物内在联系，使用大量从句172.1GrammarFeatures(6)后置形容词短语作定语多代替定语从句作后置定语，使句子简洁、紧凑，不至于累赘。1)Allradiantenergieshavewavelikecharacteristics,whichareanalogoustothoseofwavesmovingthroughwater.Allradiantenergieshavewavelikecharacteristicsanalogoustothoseofwavesmovingthroughwater.2)TheinstrumentspresentincludesomedigitaloneswhicharerelativetoDSPsTheinstrumentspresentincludesomedigitalonesrelativetoDSPs所有的辐射能都具有波的特性，与水中移动的波的特征相似。到场的仪器中还有一些与DSP有关的数字仪器（精炼）182.2RhetoricFeatures注重科学技术方面的观察、试验和客观规律、事物特征涉及的内容(如概念、原理、定理或定律、规则、方法等)大多没有特定的时间关系和时效性(1)广泛使用一般现在时(2)较多地使用图、表和公式

常使用数据、图、表和公式等非语言因素来表明科技概念、原理、定理或定律、规则、方法等。(3)逻辑语法使用多修辞特点

进行条件论述、理论分析和公式推导时，多使用逻辑语法，即表示条件、原因、语气转折、限制、假设和逻辑顺序等词汇although,because,but,if,once,only,suppose,asaresult,becauseof,dueto,so,therefore,thus,without等。192.3VocabularyFeatures(1)词汇分类专业或技术词汇

次技术词汇

isentropicrefrigerantsuperheaterturbine很多专业和学科所共有的词汇,不同专业和学科往往具有不同词义某个专业所特有的词汇，其专业性强，词义狭窄和单一。power:幂，乘方动力，功率，效率电源，电力，功率，电能Condenser：电容器，补偿机冷凝器powerplant:发电厂

动力装置：专业或技术词汇，次技术词汇，非技术词汇(等熵的)（制冷剂）(过热器)(汽轮机)202.3VocabularyFeatures

非技术词汇在普通英语或非专业英语中使用较少，但实际却属于非专业英语的词汇takein->absorb,Lookinto->examine,findout->discoverturnround->rotatemakegooduseof->utilize,change->convert212.3VocabularyFeatures(1)词汇构成1)合成法由相互独立的两个或更多的词合成得到新词名词+名词（n.+n.）→n.:Carnotcycle,phasechange,heatpump名词+形容词(n+adj.)→adj.：ice-cold名词+副词(n+adv.)→n.，adj.:feedback形容词＋名词（adj+n）→n.，adj.：Forcedconvection,thermalconductivity,形容词+名词+ed(adj.+n.+ed)→adj.:small-sized介词+名词(prep.+n.)→adj.,n.：bypass,on-line,overheat222.3VocabularyFeatures2)派生法通过对词根加上各种前缀或后缀来构成新词专业英语词汇大部分都是用派生法构成的，thermo-：thermo-dynamics，thermo-electricaliso-:isothermal;micro-300个以上:auto-260个以上:前缀（prefix）：词义变化，词类不变后缀（suffix）：词义可能变化可能不变，词类一定会变常用的前缀和后缀却多达百个，可见派生法的构词能力是非常强的。作为一个专业技术人员，至少应掌握50个常用前缀和后缀。23名词前缀前缀含义例词auto-自动，自己，自身Autocompensation(自动补偿），automation（自动化）

，autoexcitation（自激振荡）

counter-反，逆，抗，补Countermodulation（反调制）；countercurrent（逆流）

hydr(o)水，流体，氢(化)hydroenergy，hydropowerhyper-超，过Hyperfrequency（超高频），hyperplane（超平面）mini-微，小Minicomponent（小型元件），minipad（小垫片）micro-微，百万分之一Micromotor（微型电动机），microadjustment（微型焊接）

semi-半，部分，不完全semiconductor，semiempirical，semielectronicsuper-超，上，特superconductor，supergrid（超高压电网）ultra-超，过度，极端ultra-highvoltage（UHV，超高压）ultraspeedextra-超，特extra-highvoltage(EHV)24后缀含义例词-age抽象概念，如性质、状态、行为等voltage，percentage-ance,-ence抽象概念，如性质、状态、行为等resistance电阻，difference差别-ency抽象概念，如性质、状态、行为等efficiency效率，frequency频率，emergency紧急情况-ion，-tion,-sion,抽象概念，如性质、状态、行为等action作用，automation自动化,transmission传输-logy学论，技术technology技术，dermatology（皮肤医学）

，iatrology医学，electrotechnology

电工学-ness性质、状态、程度hardness硬度，deepness深度，brightness亮度，roughness粗糙度-ship情况、性质、状态、关系、地位relationship关系，friendship友好，membership会员资格，scholarship奖学金，学问，学识，fellowship伙伴关系-er,-orCondenser冷凝器,compressor压缩机，evaporator蒸发器，heatexchanger热交换器名词后缀25词缀含义例词-able,-iblemeasurable可测量的,convertible可逆的-ouscontinuous继续的simultaneous同时的-fulpowerful强大的，useful有用的-lesscolorless无色的形容词后缀副词后缀词缀含义例词-ly。。。地carefully仔细地，-ward。。。向backward逆向，反馈downward向下的eastward向东的-wise方向clockwise顺时针方向26动词后缀词缀含义例词-enbroaden加宽，harden硬化，shorten变短-fyelectrify使。。。带电，-izestandardize使标准化词缀含义例词circ圆，环circuit电路，circum圆周chron表时间synchronism同步chronic慢性的fold倍数threefold三倍,fourfold四倍,fivefold五倍meter仪器仪表ammeter安培表，voltmeter伏特表wattmeter功率表gram，graph文字，图形diagram图表,program程序,telegraph电报phone声音microphone话筒Telephone电话therm(o)热thermoelectron热电子thermoanalysis热分析词根273)词汇缩略2.3VocabularyFeatures只由词汇中的部分字母或由词组中每个词汇的首字母。CFDCOPODPReLMTDGWPCFB—Computationalfluiddynamics;—CoefficientofPerformance—ozonedepletionpotential

—Reynoldsnumber—Logmeantemperaturedifference—Global-warmingpotential—circulatingfluidizedbed282.4SymbolandFormula国际单位制中的前缀前缀符号数值中文名称例词tera-T1012兆兆（亿万）giga-G109千兆（十亿）gigahertz(GHz)10kHz～1GHzmeg(a)-M106兆

megohmmeter（兆欧计）,megohertz(MHz)kilo-k103千kilometer(km)kilovolt(kV)kilowatt(kW)kilogram(kg）hecto-h102百hectogram,deca-da101十decameterdeci-d10-1分（十分之一）decimetercenti-c10-2厘centimeter(cm)milli-m10-3毫milliampere（mA）milliammetermicro-μ10-6微microfarad（μF，微法拉）nano-n10-9纳nanometer(nm)pico-p10-12微微

picocoulomb(pC，微微库伦),picofarad(pF)femto-f10-15毫微微atto-a10-18微微微292)小数，分数，百分数2.4SymbolandFormula0.1:zeropointone,pointone,opointone,onetenth,decimalone0.01:pointzeroone,10.35:tenpointthreefive1/2:a(one)half1/3:athird1/4:onequarter1/8:aeighth2/3:two-thirds,twooverthree,twodividedbythree3/4:three-fourths,threequarters3%:threepercent0.2%:pointtwopercent5‰:fivepermill303)幂（power）根（root）xtothesecondpower

2.4SymbolandFormula:xsquare,xsquared,thesquareofx,thesecondpowerofx,ytothethirdpower

:ycube,ycubed,thecubeofy,thethirdpowerofy,:thenthpowerofa,atothenpower

:thesquarerootofthree

:thecube(third)rootofa

:thenthrootofa

312.4SymbolandFormula4)数学运算符号A+BAandB,AplusBA-BAminusBA×BAtimesB,AmultipliedbyBA÷BAoverB,AdividedbyBA±BAplusorminusBA=BAequalsB,aequalstob,aisequaltobA≠BAisnotequaltoB,AisnotBA≈BAisapproximatelyequaltoBA>BAisgreaterthanBA<BAislessthanBA>BAisgreaterthanBA<BAislessthanBA>>BAismuch(far)greaterthanBA<<BAismuchlessthanBA≥BAisgreaterthanorequaltoB.A≤BAislessthanorequaltoB.A∝BAisproportiontob,avariesdirectlyasbA:BAtoB322.4SymbolandFormula332.4SymbolandFormula34Lecture

3Englishtranslation英文翻译3.1Introductionoftranslation翻译是把一种语言的信息用另一种语言表达出来；翻译的目的是使译文的读者能得到原作者所表达的思想，得到与原文读者大致相同的感受。翻译涉及到两种语言，而不同的语言名有不同的表达方式，翻译决不是从一种语言到一种语言的简单转换，它要求译者进行创造性的实践活动。363.1Thestandardoftranslation准确明白(True)“准确”，就是说译文要准确无误地表达原文含义，不得有错。“明白”，即要求译文不仅要忠实于原文，而且应清楚明白地转达原文的意思。通顺严密(Smooth)“通顺”，是指译文符合汉语的语法要求、修辞规则和通常习惯，使读者易看易懂易速。“严密”，是说译文语言既要通畅又应严密，不要因为通顺而牺牲了原文的严密性。简练全面(Simple+General=Professional)“简练”，就是译文要简洁、精练，没有冗词赘语，不重复罗嗦。“全面”，是说译文不但要尽可能简练还应该力求全而不能因简练而造成遗漏。373.1Theprocedureoftranslation理解阶段(Understanding)理解阶段的主要环节是辩明词义和语法关系，分析各个句子成分的逻辑关系和句子的语法结构，弄清词、词组、短语、从句的确切含义和句子所叙述的专业内容，并把前后句子贯串起来理解，形成对原文的完整印象。表达阶段(Presentation)表达阶段就是在理解的基础上，以忠实于原意为前提，灵活地运用各种适当的翻译方法和技巧，写出符合汉语规范、表达习惯以及翻译标准的译文。校核阶段(checkout)校核阶段处理解与表达的进一步深化，是对原文内容进一步核实，对译文语言进一步推敲，使译文符合标准规范。383.2Theprocedureofcheckout初校着重校核内容，在初稿译出后，对照原文进行校核，看有没有漏译或错译之处。复校脱离原文，着重润饰文字，看译文是否符合译语的习惯表达法，是否符合译语规范，是否通顺。定稿初校和复校的基础广，再次对照原文，进行一次仔细认真的校核。

39Commonproblemsintranslation错误一：逐词翻译，以致译文生硬欧化；错误二：单纯追求译文通顺流畅而任意增删；40ExamplesHewantedtolearn,toknow,toteach.他想学习，增长知识，也愿意把知识教给别人。他希望博学广闻，喜欢追根穷源，好为人师。theironandsteelindustry铁和钢的工业钢铁工业Themachineworksproperly.机器工作正常。机器运转正常。413.2ThecomparisonbetweenChineseandEnglish(Ⅰ)词义的对应关系英语中的词和汉语中的词的词义范围大都只是部分对等，全部对等的词很少，一般只有专有名词和科技术语才有可能(如temperature,velocity)。词序的差异汉语是分析性语言，依靠词序表示各成分之间的关系，词序是严格的，而英语助词序比较灵活。英语和汉语的句子中主语、谓语、宾语和表语的词序大体一致，但是定语和状语的位置有时相同，有时不同。在翻译的应该注意汉语的习惯。423.2ThecomparisonbetweenChineseandEnglish(Ⅱ)定语的位置英语中可作定语的有单词、短语和定语从句，以单词作定语一般前置，以短语和从句作定语一般后置。汉语的定语一般都在被修饰词之前。主句和从句的顺序英语的复合句中表示时间和因果关系的从句的位置比较灵活，但是汉语的表达习惯是按时间顺序叙述，先发生的事件先说，后发生的事件后说，谈到因果关系时，先说明原因，后叙述结果。因此在翻译有时间和因果关系的复合句时，要注意按照汉语的习惯表达。43Lecture4Thermodynamics热力学ThermodynamicsEnergyApplicationareasAScienceofEnergyThermodynamicSystemZerothLawTheFirstLawTheSecondLawTheIncreaseofEntropyPrincipleCarnotPrinciplesetcEnergyTransformationsRelationshipstomatterpropertiesClosedsystemOpensystemAdiabaticsystemIsolatedsystemIntensivepropertiesT,P,ρ

ExtensivepropertiesV,E,H,SStateStatepostulate:Thestateofasimplecompressiblesystemiscompletelyspecifiedbytwoindependent,intensiveproperties.E.g.T(temperature)&ν(specificvolume),orP&T(onephase)Equilibrium::Temperature(T),mechanical(P),phase,chemicalPath,CycleProcessState1toState2SteadyflowprocessTK℃Triplepoint=0.01℃=273.16K273.15TransferAsetofpropertiesthatcompletelydescribestheconditionofthesystemPropertiesQuasi-equilibrium:aprocessinwhichsystemremainsinfinitesimallyclosetoanequilibriumstateatalltimes.Isothermal,Isobaric,Isometric,IsoentropicReversibleprocessIrreversibleprocessSystemBoundary/Surrounding45OverviewofThermodynamics:whatis??ThermodynamicsScienceofEnergy（能量）NamefromGreekwords:Thermoheat热thermodynamicsDynamicpower

动力热力学Thermodynamicsisasubjectthatdealswithenergy,energytransfer，energy

transformations,andrelationshipsamongthepropertiesofmatter.

（研究能量、能量传递与转换、能量与物质性质之间关系）4646Firstsuccessfulsteamenginebuildby？？

Watt？

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Overview:HistoryofThermodynamicsasascience4747FirstsuccessfulsteamenginedesignedbyThomasSavery(1697patentedasteam-poweredpumphecalledtheMiner'sFriend)ThomasNewcomencreatedthefirstpracticalsteamenginein1712.JamesWattimprovedin1763to1784(75%lesscoal)48AnimationofaschematicNewcomensteamengine.

–Steamisshownpinkandwaterisblue.

–Valvesmovefromopen(green)toclosed(red)汽缸/活塞水箱Overview:HistoryofThermodynamicsasascience48Firstandsecondlawsofthermodynamicsemergedin1850s,fromworksofLordKelvin/开尔文(1824-1907):developedtheKelvinscale(开尔文温标）ofabsolutetemperaturemeasurement;firstlyusethermodynamicsin1849.Overview:HistoryofThermodynamicsasascience4949Firstandsecondlawsofthermodynamicsemergedin1950s,fromworksofWilliamRankine/朗肯(1820-1872):developedacompletetheoryofthesteamengineandindeedofallheatengines.Writefirstthermodynamictextbookin1859.Overview:HistoryofThermodynamicsasascience5050Firstandsecondlawsofthermodynamicsemergedin1950s,fromworksofRudolphClausius/克劳修斯(1822-1888):in1850,firststatedthebasicideasofthesecondlawofthermodynamics.In1865heintroducedtheconceptofentropy.51Overview:HistoryofThermodynamicsasascience51Firstandsecondlawsofthermodynamicsemergedin1950s,fromworksofSadiCarnot/卡诺(1796–1832)gavethefirstsuccessfultheoreticalaccountofheatengines,nowknownastheCarnotcycle,layingthefoundationsofthesecondlawofthermodynamics.Otherslike:Carnotefficiency,Carnotheatengine.52Overview:HistoryofThermodynamicsasascience52Firstandsecondlawsofthermodynamicsemergedin1950s,fromworksofJamesJoule/焦耳(1818-1889)discoveredrelationshipofheattomechanicalwork,whichledtothetheoryofconservationofenergy(firstlawofthermodynamics).SIunitofenergy,thejoule,isnamedafterhim.53Overview:HistoryofThermodynamicsasascience53LordKelvin/开尔文

(1824-1907)WilliamRankine/朗肯

(1820-1872)RudolphClausius/克劳修斯

(1822-1888)SadiCarnot/卡诺

(1796–1832)JamesJoule/焦耳(1818-1889)54Overview:HistoryofThermodynamicsasascience54Overview:ApplicationareasofthermodynamicsAllactivitiesinnatureinvolvesomeinteractionbetweenenergyandmatter,fromwhichthermodynamicsisinvolved.Manyengineeringsystems:5555Otheraspectsoflife:….Thermodynamicsisimportantandveryusefulforustounderstandtherealactivitiesaroundus.56Overview:Applicationareasofthermodynamics56Basic/importantconceptsTostudyathermodynamicalsystemsystem系统surroundings外界boundary边界closedsystemcontrolmass闭口,opensystemcontrolvolumes开口

property属性，参数equilibriumstate平衡态研究教室的取暖情况

教室/系统室外/外界墙/边界关门、窗/闭口系,开门、窗/开口50m2，25℃/属性，参数暖和、不冷/状态,

无忽冷忽热/平衡态白天-晚上/过程白天-晚上-白天/循环5757Basicconcepts:System

andboundaryThermodynamicSystem（系统）:aquantityofmatteroraregioninspacechosenforstudy(人为分割出来的，作为热力学分析对象的有限物质系统).

Boundary(边界):thesurfacethatseparatesthesystemfromitssurroundings.thickness;containnomass;notZerooccupyanyvolumeSurroundings(外界):massandregionoutsidethesystem585858Systemclassificationbasedontheexchangeof:Mass-物质,M(kg)QuantityofHeat-热量,Q(kJ)Work-功,W(kJ)Basicconcepts:SystemClassification59591234Mass,Mheat,QWork,W1

OpenSystem(Controlvolume)：Non-Isolatedsystem+relatedsurrounding＝isolatedsystem1+2

ClosedSystem(Controlmass)1+2+3

Adiabaticclosedsystem绝热系统1+2+3+4

IsolatedsystemBasicconcepts:SystemClassification60601234Mass,Mheat,QWork,W1

OpenSystem(Controlvolume)：betweenasystemandsurrounding,thereareexchangesofbothenergy(heatandwork)andmass(开口系统：热力系统与外界之间不仅有能量交换而且有物质交换)开口系统通常是在某一划定的空间范围内进行的，所以又叫控制容积，或控制体Basicconcepts:SystemClassification616162Basicconcepts:Open

System621234Mass,Mheat,QWork,W1+2

ClosedSystem(Controlmass):betweenasystemandsurrounding,thereareexchangesofenergy(heatandwork),butnomassexchange.(闭口系统：热力系统与外界之间只有能量交换，没有物质交换)闭口系统质量保持不变，又叫控制质量Basicconcepts:SystemClassification636364Basicconcepts:Closed

System641234Mass,Mheat,QWork,W1+2+3

AdiabaticclosedsystemBasicconcepts:SystemClassificationAdiabaticsystem:betweenasystemandsurroundings,therearenoexchangeofheat.(绝热系统：热力系统与外界之间无热量交换的系统)65651234Mass,Mheat,QWork,W1+2+3+4

Isolatedsystem：betweenasystemandsurrounding,therearenoexchangesofbothenergy(heatandwork)andmass(孤立系统：热力系统与外界之间既没有能量交换，也没有物质交换)Basicconcepts:SystemClassification66661234Mass,Mheat,QWork,W1

OpenSystem(Controlvolume)：1+2

ClosedSystem(Controlmass)1+2+3

Adiabaticclosedsystem1+2+3+4

IsolatedsystemBasicconcepts:SystemClassification6767RealorimaginaryBasicconcepts:BoundaryFixedormovingBoundary(边界):thesurfacethatseparatesthesystemfromitssurroundings.Zerothickness;containnomass;notoccupyanyvolume.

68FixedormovingRealorimaginaryProperchoiceofthesystem/boundarymaygreatlysimplifytheanalysis68Properties(参数)ofSystemProperty:anycharacteristicofasystem.Intensive/强度量:thevalueisindependentofthemass,T,P,ρExtensive/广延量:thevaluedependsonsizeorextentofasystem,e.g:totalmass,totalvolumeV,totalenergyE.ThecriteriontoidentifySpecificproperties:extensivepropertiesperunitmass，v，e,u,s,etc.广延量

强度量69是否具有可加性

e.g.:P.T,V,m,

69Properties(参数)ofSystemTemperature,T:K,℃,℉Pressure,P:Pa,kPa,bar,atm

Density,ρ:massperunitvolume

ρ=m/V(kg/m3)

ρdependsonPandTMostgases

ρ:isproportionaltopressureandinverselyproportionaltotemperatureLiquidsandsolidsρdependmoreonT,lessonP.Waterdensity:ρmax@4℃=1000kg/m3Specificvolume,ν:volumeperunitmassν=V/m=1/ρSpecificweight,weightofaunitvolumeγ=ρgU/内能(internalenergy)，H/焓（enthalpy），S/熵(entropy)

7070Stateandequilibriumofasystem State(状态):asetofpropertiesthatcompletelydescribesaconditionofthethermodynamicssystem.Atagivenstate,allthepropertiesarefixedIfonepropertyvalueischanged,thestatechangestoadifferentoneEquilibrium(平衡状态):astateofbalance.Nounbalancedpotentials(ordrivingforces)withinthesystem（系统内没有变化的趋势）Nochangesifasystemisisolatedfromitssurroundings(若隔离外界，则系统状态保持不变)Thermalequilibrium:nochangeintemperatureMechanicalequilibrium:nochangeinpressurewithtimePhaseequilibrium:nochangeofeachphaseChemicalequilibrium:nochangeinchemicalcomposition71state1Thermalequilibrium71ThestatepostulateStatepostulate(状态公理):thestateofasimplecompressiblesystemiscompletelyspecifiedbytwoindependent,intensiveproperties.(对于简单可压缩系统，只要有两个独立状态参数即可确定一个状态)Asimplecompressiblesystem:noexternalforcefieldslike:electrical,magnetic,gravitational,motionandsurfacetensioneffects.Twopropertiesareindependent:onecanchangewhileotheroneisconstant.T&v,T&P(forsinglephasesystem)7272Processesandcycles（过程和循环）Process（过程）:anychangethatasystemundergoesfromoneequilibriumstatetoanother.Theprocesspathindicatesaseriesofequilibriumstatesthroughwhichthesystempassesduringaprocessandhassignificanceforquasi-equilibriumprocessesonly.Cycle(循环):

asystemreturnstoitsinitialstateattheendoftheprocess.7373Quasi-equilibrium(quasi-static)process（准平衡过程）:theprocessproceedsinfinitesimallyclosetoanequilibriumstateatalltimes.(系统在变化所有阶段都无限接近于平衡状态的过程)Slowenoughtoletsystemadjustitselfinternallyandtokeepnopropertiesofcertainpartchangefaster.（系统要足够慢，系统工质在平衡阶段被破坏后的自动回复时间，即所谓弛豫时间非常短，系统内有足够时间来恢复平衡）isidealizedprocess,notactualprocess（是理想过程）.Useful（热力学分析中的作用）:EasytoanalyzeWorkproducingdevicesdelivermostworkasstandardtocomparetoactualones.7474Reversibleprocess（可逆过程）:aprocessthatcanbereversedwithoutleavinganytraceonthesurroundings;（当完成了某一过程之后，如果有可能使工质沿相同的路径逆行而回复到原来状态，并使相互作用中所涉及的外界亦回复到原来状态，而不留下任何变化：这一过程就叫可逆过程）Irreversibleprocess（不可逆过程）75Isothermalprocess（等温过程）:nochangeinTIsobaricprocess（等压过程）:nochangeinPIsochoricprocess（等容过程）:nochangeinspecificvolumeIsoentropicprocess（等熵过程）:nochangeinentropy75Proportional：成比例的Energyisconserved:itcannotbecreatedordestroyed,butcanchangefromoneformtoanother.Energystored=Energyentering-Energyleaving+EnergygeneratedinthesystemthesystemthesysteminthesystemGenernalformofenergy-balanceequation:76Inessence,theSecondlawofthermodynamicsstatesthat,inanisolatedsystem,entropycanbeproduced,butitcanneverbedestroyed.77HEATENGINES

Workcanbeconvertedtoheatdirectlyandcompletely,butconvertingheattoworkrequirestheuseofsomespecialdevices.Thesedevicesarecalledheatengines.78HEATENGINESHeatenginesdifferconsiderablyfromoneanother,butallcanbecharacterizedbythefollowing:1.Theyreceiveheatfromahigh-temperaturesource(solarenergy,oilfurnace,nuclearreactor,etc.).2.Theyconvertpartofthisheattowork(usuallyintheformofarotatingshaft).3.Theyrejecttheremainingwasteheattoalowtemperaturesink(theatmosphere,rivers,etc.).4.Theyoperateonacycle.79Thework-producingdevicethatbestfitsintothedefinitionofaheatengineisthesteampowerplant,whichisanexternal-combustionengine.80Qin=amountofheatsuppliedtosteaminboilerfromahigh-temperaturesource(furnace)Qout=amountofheatrejectedfromsteamincondensertoalow-temperaturesink(theatmosphere,ariver,etc.)Wout=amountofworkdeliveredbysteamasitexpandsinturbineWin

=amountofworkrequiredtocompresswatertoboilerpressure81Thenetworkoutputofthispowerplantissimplythedifferencebetweenthetotalworkoutputoftheplantandthetotalworkinput82Thenetworkcanalsobedeterminedfromtheheattransferdataalone.Thefourcomponentsofthesteampowerplantinvolvemassflowinandout,andthereforetheyshouldbetreatedasopensystems.Thesecomponents,togetherwiththeconnectingpipes,however,alwayscontainthesamefluid(notcountingthesteamthatmayleakout,ofcourse).Nomassentersorleavesthiscombinationsystem,whichisindicatedbytheshadedarea83Thus,itcanbeanalyzedasaclosedsystem.Recallthatforaclosedsystemundergoingacycle,thechangeininternalenergyUiszero,andthereforethenetworkoutputofthesystemisalsoequaltothenetheattransfertothesystem.84Carnnotcycle85868788899091Thermalefficiencyincreaseswithanincreaseintheaveragetemperatureatwhichheatissuppliedtothesystemorwithadecreaseintheaveragetemperatureatwhichheatisrejectedfromthesystem.Thesourceandsinktemperaturesthatcanbeusedinpracticearenotwithoutlimits,however.

92Thehighesttemperatureinthecycleislimitedbythemaximumtemperaturethatthecomponentsoftheheatengine,suchasthepistonortheturbineblades,canwithstand.Thelowesttemperatureislimitedbythetemperatureofthecoolingmediumutilizedinthecyclesuchasalake,ariver,ortheatmosphericair.93RANKINECYCLE:

THEIDEALCYCLE

FORVAPORPOWERCYCLES94Rankinecycle,whichistheidealcycleforvaporpowerplants.TheidealRankinecycledoesnotinvolveanyinternalirreversibilitiesandconsistsofthefollowingfourprocesses:1-2Isentropiccompressioninapump2-3Constantpressureheatadditioninaboiler3-4Isentropicexpansioninaturbine4-1Constantpressureheatrejectioninacondenser95Waterentersthepumpatstate1assaturatedliquidandiscompressedisentropicallytotheoperatingpressureoftheboiler.Thewatertemperatureincreases