热能与动力工程专业英语

强度量：intensivepropertiesdonotdependonmass（e,g,p,ρ,ν=1/ρ,uandh）,extensivepropertiesdependonthetotalmassofthesystem（e,g,V,M,U,andH）.Uppercaselettersareusuallyusedforextensiveproperties.准平衡：equilibrium：statesofasystemaremostconvenientlydescribedwhenthesystemisinequilibrium,i.e.itisinsteady-state.Oftenwewillconsiderprocessthatchange“slowly”-termedquasi-equilibriumorquasi-staticprocess.Aprocessisquasi-equilibriumifthetimerateofchangeoftheprocessisslowrelativetothetimeittakesforthesystemtoreachthermodynamicequilibrium.Itisnecessarythatasystembequasi-equilibriumbeforeapplyingmanyofthethermodynamicsrelationstothatsystem.热力学第一二定律：Insimplestterms,thelawofthermodynamicsdictatethespecificforthemovementofheatandwork.Basically,theFirstLawofThermodynamicisastatementoftheconservationofenergy-theSecondLawisastatementaboutthedirectionofthatconservation-andtheTiredLawisastatementaboutreachingabsoluteZero.Thefirstlawofthermodynamicisastatementoftheprincipleofconservationofenergy.Itcanalsobeconsideredasdefiningaproperty,theinternalenergy.TheSecondlawofThermodynamicstatesthatinallenergyexchanges,ifnoenergyentersorleavesthesystem,thepotentialenergyofthestatewillalwaysbelessthanthatoftheinitialstates.Thisisalsocommonlyreferredtoasentropy.举例说明热力学定律应用：acupofhotcoffeeleftonatableeventuallycools,butacupofcoolcoffeeinthesameroomnevergetshotbyitself.Thehigh-temperatureenergyofthecoffeeisdegraded(transformedintoalessusefulformatalowertemperature)onceitistransferredtothesurroundingair.Anordinaryhouseis,insomerespects,anexhibitionhallfilledwithwomdersofthermodynamics.Manyordinaryhouseholdutensilsandapplicancesaredesigned,inwholeorinpart,byusingtheprinciplesofthermodynamics.Someexamplesincludetheelectricorgasrange,theheatingandair-conditionsystems,therefrigerator,thehumidifier,thepressurecooker,thewaterheater,theiron,andeventhecomputer,andtheTV.Onalargescale,thermodynamicsplaysamajorpartinthedesignandanalysisofautomotiveengines,rockets,jetengine,andconventionalornuclearpowerplans,solarcollectors,andthedesignofvehicleformordinarycarstoairplanes.绝热系统：isolatedsystems：notexchangeingheat,matterorworkwiththeirenvironment.开口系统：exchangingenergy(heatandwork)andmatterwiththeirenvironment.闭口系统：exchangeingenergy(heatandwork)butnotmatterwiththeirenvironment.孤立系统：rigidboundary:notallowingexchangeofwork.辐射换热:Themechanisminthiscaseiselectromagneticradiation.Weshalllimitourdiscussiontoelectromagneticradiationwhichispropagatedasaresultofatemperaturedifference;thisiscalledthermalradiation.对流传热:whenafluidatrestorinmotionisincontactwithasurfaceatatemperaturedifferentfromtheplate,energyflowsinthedirectionofthelowertemperatureasrequiredbytheprincipleofthermodynamics.wesaythatheatisconvectedaway,andwecalltheprocessconvectionheattransfer.对流传热的方式:Therearetwoconvectionmodes:forcedconvectionandnaturalconvection.Ifaheatedplatewereexposedtoambientroomairwithoutanexternalsourceofmotion,amovementoftheairwouldbeexperiencedasaresultofthedensitygradientsneartheplate.Wecallthisnatural,orfree,convectionasopposedtoforcedconvection,whichisexperiencedinthecaseofthefanblowingairoveraplate.传热学:Heattransferisthesciencethatseekstopredicttheenergytransferthatmaytakeplacebetweenmaterialbodiesasaresultofatemperaturedifference.传热学和热力学的区别:Thermodynamicsteachesthatthisenergytransferisdefinedasheat.Thescienceofheattransferseeksnotmerelytoexplainhowheatenergymaybetransferred,butalsotopredicttherateatwhichtheexchangewilltakeplaceundercertainspecifiedconditions.Thefactthataheat-transferrateisthedesiredobjectiveofananalysispointsoutthedifferencebetweenheattransferandthermodynamics.Thermodynamicsdealswithsystemsinequilibrium;itmaybeusedtopredicttheamountofenergyrequiredtochangeasystemfromoneequilibriumstatetoanother;itmaynotbeusedtopredicthowfastachangewilltakeplacesincethesystemisnotinequilibriumduringtheprocess.Heattransfersupplementsthefirstandsecondprinciplesofthermodynamicsbyprovidingadditionalexperimentalruleswhichmaybeusedtoestablishenergy-transferrates.Asinthescienceofthermodynamics,theexperimentalrulesusedasabasisofthesubjectofheattransferarerathersimpleandeasilyexpandedtoencompassavarietyofpracticalsituations.影响辐射传热的因素：Totakeaccountofthe“gray”natureofsuchsurfaceweintroduceanotherfactorintoEquation,calledtheemissiveε:whichrelatestheradiationofthe“gray”surfacetothatofanidealblacksurface.Wemusttakeintoaccountthefactthatnotalltheradiationleavingonesurfacewillreachtheothersurfacesinceelectromagnicradiationtravelsinstraightlinesandsomewillbelosttothesurroundings.热能与动力工程thermalenergyandpowerengineering能量转化energy-transfer比例常数proportionalityconstant比例系数proportionalityfactor活性中心activecenter对流传热convectionheattransfer电磁辐射electromagneticradiation角系数viewfactor准静态过程quasi-staticprocess准平衡quasi-equilibrium静态平衡staticequilibrium强度参数intensiveproperty广延参数extensiveproperty燃烧机理combustionmechanism平均分子运动averagemolecularmotion热反应堆thermalreactor热力学性质thermodynamicproperty摩尔热容molarheatcapacity动能kineticenergy压缩因子compressibilityfactor温度传感器temperaturesensor测量电路measurementcircuit电压输出voltageoutput静电荷electrostaticcharge励