工程热力学英语习题课件

Chapter1

BasicConceptsAgasinapiston-cylinderdeviceiscompressed,andasaresultitstemperaturerises.Isthisaheatorworkinteraction?OnaP-vdiagram,whatdoestheareaundertheprocesscurverepresent?Determinetheenergyrequiredtoacceleratea2000-kgcarfrom20to70km/honanuphillroadwithaverticalriseof40m.Chapter1

BasicConceptsAgas14.Consideradevicewithoneinletandoneexit.Ifthevolumeflowratesattheinletandattheexitarethesame,istheflowthroughthedevicenecessarilysteady？Why?5.A2m3rigidtankcontainsnitrogengasat500kPaand300K.Nowheatistransferredtothenitrogeninthetankandthepressureofnitrogenrisesto800kPa.Theworkdoneduringthisprocessis(A)600kJ(B)1000kJ(C)0kJ(D)500kJ(E)1600kJ4.Consideradevicewitho26.A2m3rigidtankcontainsnitrogengasat500kPaand300K.Nowheatistransferredtothenitrogeninthetankandthepressureofnitrogenrisesto800kPa.Theworkdoneduringthisprocessis

(A)600kJ(B)1000kJ(C)0kJ(D)500kJ(E)1600kJ6.A2m3rigidtankcontains3CHAPTER2

PROPERTIESOFPURESUBSTANCES2.1Arigidtankcontains5kgofanidealgasat4atmand40℃.Nowavalveisopened,andhalfofmassofthegasisallowedtoescape.Ifthefinalpressureinthetankis1.5atm.thefinaltemperatureinthetankis[a]-38℃[b]30℃[c]40℃[d]53℃[e]144℃2.2Arigidvesselcontainssteamat20MPaand400℃.Themassofthesteamis[a]5.0kg[b]0.322kg[c]322kg[d]503kg[e]680kgCHAPTER2

PROPERTIESOFPURES42.3Arigidtankisfilledwithsaturatedliquid-vapormixtureofwaterat200kPa.If20percentofthemassisliquidandthe80percentofthemassisvapor,thetotalmassinthetankis[a]705kg[b]500kg[c]258kg[d]635kg[e]28092.3Arigidtanki5Chapter3

ThefirstLawofThermodynamicsAreversiblecycleplotsasaperfectcircleonaT-Sdiagramwithmaximumandminimumtemperatures600Kand300Kandamaximumandminimumentropyof600kJ/Kand300kJ/K.Chapter3

ThefirstLawofTh6a)Whatisthenetworkofthiscycle?b)Indicatethepathinthecyclealongwhichheatisrejected.Howdoyouknow?(Asentenceortwoisrequired,perhapsbolsteredbyanequation).c)Whatisthethermodynamicefficiencyofthiscycle?a)Whatisthenetworkofth72.Thesketchbelowshowsaperfectlyinsulatedcontainerwithtwocompartmentsseparatedbyanon-adiabatic,frictionlesspiston.Bothcompartmentsareatthesamepressure(PA=PB)andcontainanequalamountofthesamegas(mA=mB).InitiallycompartmentAisatahighertemperaturethancompartmentB(TA>TB).2.Thesketchbelowshows8工程热力学英语习题课件9a)Whichway,ifatall,doesthepistonmove?Indicatebyanarrowonadrawinginyourexambook(Asentenceortwoisexpected,perhapsbolsteredbysomeequations).b)IsthefinalinternalenergyUfinalofthesystem(bothcompartmentstogether)lower,equalorhigherthaninitialinternalenergyUinitialofthesystem?Why?(Asentenceortwoisexpected,perhapsbolsteredbysomeequations.)a)Whichway,ifatall,does10c)WhatisthefinaltemperatureofthesystemTfinalexpressedintermsofTAandTB?b)WhatisthechangeinentropyofcompartmentA?WhatisthechangeinentropyofcompartmentB?e)Whatisthechangeinentropyofthesurroundings?f)Isthisprocessreversibleorirreversible?Howdoyouknow?(Note:youdonothavetoproveyouranswermathematicallytogetfullcredit.Explaininasentencehowyouknowwhethertheprocessisreversibleorirreversible)c)Whatisthefinaltemperatu1110kgofaircontainedinapistoncylinderapparatusat5bar,300K,expandsisothermallyuntilthepressureis1bar.Determine:(i)theworkdone.(ii)theinternalenergychangeoftheair.(iii)theheattransfer.Assumethatairbehavesasanidealgasandpressurevariationisgradualandcontinuous.10kgofaircontainedinapi12AsystemiscapableofexecutingacyclicprocessasindicatedinthePVsketch;itmaybeexecutedeitherclockwiseabcaorcounterclockwiseadca.(a)Whengoingclockwisetostatec,80KJofheatflowfromthesystem.Findtheworkalongthepathca.(b)Whengoingcounterclockwisetostatec,70KJofheatflowfromthesystem.Findtheworkduringtheprocessadc.Asystemiscapableofexecuti13工程热力学英语习题课件14CHAPTER5THESECONDLAWOFTHERMODYNAMICS5.1Thedrinkingwaterneedsofanofficearemetbycoolingtabwaterinarefrigeratedwaterfountainfrom22℃to8℃atanaveragerateof8kg/h.IftheCOPofthisrefrigeratoris3.1,therequiredpowerinputtothisrefrigeratoris[a]28W[b]42W[c]88W[d]130W[e]403WCHAPTER55.1Thedrinkingwa155.2Aheatenginecycleisexecutedwithsteaminthesaturationdome.Thepressureofsteam1MPaduringheataddition,and0.5MPaduringheatrejection.Thehighestpossibleefficiencyofthisheatengineis[a]6.2％[b]15.6％[c]50.0％[d]93.8％[e]100％5.2Aheatenginecycleisex165.3Aheatenginereceivesheatfromasourceat100℃andrejectsthewasteheattoasinkat50℃.Ifheatissuppliedtothisengineatarateof100kj/s,themaximumpowerthisheatenginecanproduceis[a]25.4kW[b]55.4kW[c]174.6kW[d]95.0kW[e]100.0kW5.3Aheatenginereceiveshea175.4Steamiscompressedfrom8MPaand300℃to10MPaisentropically.Thefinaltemperatureofthesteamis[a]290℃[b]300℃[c]320℃[d]330℃[e]340℃5.4Steamiscompressedfrom185.5Heliumgasiscompressedfrom1atmand25℃toapressureof10atmadiabatically.Thelowesttemperatureofheliumaftercompressionis[a]25℃[b]63℃[c]250℃[d]384℃[e]476℃5.5Heliumgasiscompressed195.6Steamexpandsinanadiabaticturbinefrom10MPaand500℃to0.1MPaatarateof8kg/s.Ifsteamleavestheturbineassaturatedvapor,thepoweroutputoftheturbineis[a]5586kw[b]698kw[c]2136kw[d]12,452kw[e]26,990kw5.6Steamexpandsinanadiaba205.7Aunitmassofasubstanceanirreversibleprocessfromstate1tostate2whilegainingheatfromthesurroundingsattemperatureTintheamountofq.Iftheentropyofthesubstanceisatstate1,andatstate2,theentropychangeofthesubstancesduringthisprocessis[a][b][c][d][e]5.7Aunitmassofasubstanc215.8Airiscompressedfromroomconditionstoaspecifiedpressureinareversiblemannerbytwocompressor:oneisothermalandtheotheradidbatic.Iftheentropychangeofairsduringthereversibleadiabaticcompression,thecorrectstatementregardingentropychangeofairperunitmassis[a][b][c][d][e]5.8Airiscompressedfromr225.9Heatislostthroughaplanewallsteadilyatarateof600W.Iftheinnerandoutersurfacetemperatureofthewallare20℃and5℃,respectively,therateofentropygenerationwithinthewallis[a]0.11W/K[b]4.21W/K[c]2.10W/K[d]142.1W/K[e]90.0W/K5.9Heatislostthroughapla235.10Airat15℃iscompressedsteadilyandisothermallyfrom100KPato700KPaatarateof0.12kg/s.Theminimumpowerinputtothecompressoris[a]1.0kW[b]11.2kW[c]25.8kW[d]19.3kW[e]16.1kW5.10Airat15℃iscompress245.11Airistobecompressedsteadilyandisentropicallyfrom1atmto16atmbyatwo-stagecompressor.Tominimizethetotalcompressionwork,theintermediatepressurebetweenthetwostagesmustbe[a]2atm[b]4atm[c]8atm[d]10atm[e]12atm5.11Airistobecompresseds255.12Liquidwaterentersanadiabaticpipingsystemat15℃atarateof5kg/s.Ifthewatertemperaturerisesby0.5℃duringflowduetofriction.therateofentropygenerationinthepipeis[a]36W/K[b]29W/K[c]685W/K[d]920W/K[e]8370W/K5.12Liquidwaterentersanad265.13Steamentersanadiabaticturbineat4MPaand500℃atarateof15kg/s,andexitsat0.2MPaand300℃.Therateofentropygenerationintheturbineis[a]0.8kW/K[b]1.2kW/K[c]12.0kW/K[d]15.1kW/K[e]17.4kW/K5.13Steamentersanadiabatic275.13Aquantityofairundergoesathermodynamiccycleconsistingofthreeprocessesinseries.Process1-2:constant-volumeheatingfromP1=0.1MPa,T1=288K,V1=0.02toP2=0.42MPa;Process2-3:constant-pressurecooling;Process3-1:isothermalheatingtotheinitialstate;EmployingtheidealgasmodelwithCp=1kJ/kgK,evaluatethechangeinentropyforeachprocess.Sketchthecycleonp-vcoordinates.5.13Aquantityofairundergoe28CHAPTER8THERMODYNAMICSOFHIGH-SPEEDGASFLOW8.1Inwhichmediumwillsoundtravelfastestforagiventemperature:air,helium,orargon?8.2Isitpossibletoaccelerateagastoasupersonicvelocityinaconvergingnozzle?8.3Airentersaconverging-divergingnozzleatapressureof1.2MPawithnegligiblevelocity.Whatisthelowestpressurethatcanbeobtainedatthethroatofthenozzle?CHAPTER88.1Inwhichmedium298.4Airentersanozzleat0.2MPa,350K,andavelocityof150m/s.Assumingisentropicflow,determinethepressureandtemperatureofairatalocationwheretheairvelocityequalsthevelocityofsound.Whatistheratiooftheareaatthislocationtotheentrancearea?8.5Airentersaconverging-divergingnozzleat0.8MPawithnegligiblevelocity.Assumingtheflowtobeisentropic,determinethebackpressurethatwillresultinanexitMachnumberofAirentersanozzleat0.230Airentersanadiabaticnozzleat800Kand140KPaandemergesat7KPa.Theisentropicefficiencyofthenozzleisknowntobe0.96.Determinethedischargevelocity.SketchtheprocessonaT-Sdiagramandlabelthestates.YoumayassumetheworkingfluidisaperfectgaswithCp=1kJ/kgK.Airentersanadiabati318.6Steamentersanconvergingnozzleat30.MPaand600℃withanegligiblevelocity,anditexitsat1.8MPa.Foranozzleexitareaof24c㎡,determinetheexit.Velocity,massflowrate,andexitMachnumberifthenozzle(a)isisentropicand(b)hasanefficiencyof90percent8.6Steamentersanconverging32CHAPTER9GASPOWERCYCLES9.1ACarnotcycleoperatesbetweenthetemperaturelimitsof300Kand1500K,andproduces600kwofnetpower.Therateofentropychangeoftheworkingfluidduringtheheatadditionprocessis[a]0[b]0.4kW/K[c]0.5kW/K[d]2.0kW/K[e]5.0kW/KCHAPTER99.1ACarnotcycleo33a)Asimpleengineusesaperfectgasastheworkingfluidinapiston-cylindersystem.Thegasisfirstheatedatconstantpressurefromstate1tostate2,thencooledatconstantvolumetostate3whereT3=T1,andthencooledatconstanttemperature,therebyreturningtostate1.Deriveexpressionsfortheamountsofenergytransferasworkandheat(perkgofgas)foreachprocessintermsofthetemperaturesandpressuresateachstateandtheconstantsofthegas.SupposeT1=300K,P1=0.2MPa,T2=800K,K=Cp/Cv=1.4.Calculatethecycleefficiency(networkoutput/energyinputasheat)a)Asimpleengineusesaperf34b)Whentheengineofpart(a)isreversed,itbecomesarefrigerationdevice.Calculatetheamountofenergytransferasheatfromthecoldspaceforthiscycle(perkgofgas),andthecycleCOP(energytransferasheatfromcoldspace/networkinput).Youcanassumeairfortheworkingfluid.b)Whentheengineofpart(35CHAPTER10REFRIGERATIONCYCLES10.1Arefrigeratorremovesheatfromarefrigeratedspaceat-5℃atarateof0.35kj/sandrejectsittoanenvironmentat20℃.Theminimumrequirespowerinputis[a]30W[b]33W[c]56W[d]124W[e]350WCHAPTER1010.1Arefrigerator3610.2AnidealvaporcompressionrefrigerationcyclewithR-134aastheworkingfluidoperatesbetweenthepressurelimitsof140kPaand900kpa.Themassfractionoftherefrigerantthatisintheliquidphaseattheinletoftheevaporatoris[a]0.75[b]0.65[c]0.50[d]0.35[e]0.2510.2Anidealvaporcompressi3710.3ConsiderarefrigerationthatoperatesonthevaporcompressionrefrigerantcyclewithR-134aastheworkingfluid.Therefrigerantentersthecompressorassaturatedvaporat140kPa,andexitsat800kPaand60℃,andleavesthecondenserassaturatedliquidat800kPs.Thecoefficientofperformanceofthisrefrigeratoris[a]0.41[b]0.1[c]1.8[d]2.5[e]3.410.3Considerarefrigeration38Thereare528kJ/minofheatremovedfromabodybyarefrigeratoroperatingbetweenthelimitsof244.5Kand305.5K.IfitscoefficientofperformanceisthreefourthsofthatofaCarnotrefrigeratorworkingbetweenthesametemperaturelimits,find(a)theheatrejectedand(b)theworkinput,kw.(c)WhataretheCOPandtheheatifthisdeviceisusedtodeliverheat?

Thereare528kJ/minofheatr39Chapter1

BasicConceptsAgasinapiston-cylinderdeviceiscompressed,andasaresultitstemperaturerises.Isthisaheatorworkinteraction?OnaP-vdiagram,whatdoestheareaundertheprocesscurverepresent?Determinetheenergyrequiredtoacceleratea2000-kgcarfrom20to70km/honanuphillroadwithaverticalriseof40m.Chapter1

BasicConceptsAgas404.Consideradevicewithoneinletandoneexit.Ifthevolumeflowratesattheinletandattheexitarethesame,istheflowthroughthedevicenecessarilysteady？Why?5.A2m3rigidtankcontainsnitrogengasat500kPaand300K.Nowheatistransferredtothenitrogeninthetankandthepressureofnitrogenrisesto800kPa.Theworkdoneduringthisprocessis(A)600kJ(B)1000kJ(C)0kJ(D)500kJ(E)1600kJ4.Consideradevicewitho416.A2m3rigidtankcontainsnitrogengasat500kPaand300K.Nowheatistransferredtothenitrogeninthetankandthepressureofnitrogenrisesto800kPa.Theworkdoneduringthisprocessis

(A)600kJ(B)1000kJ(C)0kJ(D)500kJ(E)1600kJ6.A2m3rigidtankcontains42CHAPTER2

PROPERTIESOFPURESUBSTANCES2.1Arigidtankcontains5kgofanidealgasat4atmand40℃.Nowavalveisopened,andhalfofmassofthegasisallowedtoescape.Ifthefinalpressureinthetankis1.5atm.thefinaltemperatureinthetankis[a]-38℃[b]30℃[c]40℃[d]53℃[e]144℃2.2Arigidvesselcontainssteamat20MPaand400℃.Themassofthesteamis[a]5.0kg[b]0.322kg[c]322kg[d]503kg[e]680kgCHAPTER2

PROPERTIESOFPURES432.3Arigidtankisfilledwithsaturatedliquid-vapormixtureofwaterat200kPa.If20percentofthemassisliquidandthe80percentofthemassisvapor,thetotalmassinthetankis[a]705kg[b]500kg[c]258kg[d]635kg[e]28092.3Arigidtanki44Chapter3

ThefirstLawofThermodynamicsAreversiblecycleplotsasaperfectcircleonaT-Sdiagramwithmaximumandminimumtemperatures600Kand300Kandamaximumandminimumentropyof600kJ/Kand300kJ/K.Chapter3

ThefirstLawofTh45a)Whatisthenetworkofthiscycle?b)Indicatethepathinthecyclealongwhichheatisrejected.Howdoyouknow?(Asentenceortwoisrequired,perhapsbolsteredbyanequation).c)Whatisthethermodynamicefficiencyofthiscycle?a)Whatisthenetworkofth462.Thesketchbelowshowsaperfectlyinsulatedcontainerwithtwocompartmentsseparatedbyanon-adiabatic,frictionlesspiston.Bothcompartmentsareatthesamepressure(PA=PB)andcontainanequalamountofthesamegas(mA=mB).InitiallycompartmentAisatahighertemperaturethancompartmentB(TA>TB).2.Thesketchbelowshows47工程热力学英语习题课件48a)Whichway,ifatall,doesthepistonmove?Indicatebyanarrowonadrawinginyourexambook(Asentenceortwoisexpected,perhapsbolsteredbysomeequations).b)IsthefinalinternalenergyUfinalofthesystem(bothcompartmentstogether)lower,equalorhigherthaninitialinternalenergyUinitialofthesystem?Why?(Asentenceortwoisexpected,perhapsbolsteredbysomeequations.)a)Whichway,ifatall,does49c)WhatisthefinaltemperatureofthesystemTfinalexpressedintermsofTAandTB?b)WhatisthechangeinentropyofcompartmentA?WhatisthechangeinentropyofcompartmentB?e)Whatisthechangeinentropyofthesurroundings?f)Isthisprocessreversibleorirreversible?Howdoyouknow?(Note:youdonothavetoproveyouranswermathematicallytogetfullcredit.Explaininasentencehowyouknowwhethertheprocessisreversibleorirreversible)c)Whatisthefinaltemperatu5010kgofaircontainedinapistoncylinderapparatusat5bar,300K,expandsisothermallyuntilthepressureis1bar.Determine:(i)theworkdone.(ii)theinternalenergychangeoftheair.(iii)theheattransfer.Assumethatairbehavesasanidealgasandpressurevariationisgradualandcontinuous.10kgofaircontainedinapi51AsystemiscapableofexecutingacyclicprocessasindicatedinthePVsketch;itmaybeexecutedeitherclockwiseabcaorcounterclockwiseadca.(a)Whengoingclockwisetostatec,80KJofheatflowfromthesystem.Findtheworkalongthepathca.(b)Whengoingcounterclockwisetostatec,70KJofheatflowfromthesystem.Findtheworkduringtheprocessadc.Asystemiscapableofexecuti52工程热力学英语习题课件53CHAPTER5THESECONDLAWOFTHERMODYNAMICS5.1Thedrinkingwaterneedsofanofficearemetbycoolingtabwaterinarefrigeratedwaterfountainfrom22℃to8℃atanaveragerateof8kg/h.IftheCOPofthisrefrigeratoris3.1,therequiredpowerinputtothisrefrigeratoris[a]28W[b]42W[c]88W[d]130W[e]403WCHAPTER55.1Thedrinkingwa545.2Aheatenginecycleisexecutedwithsteaminthesaturationdome.Thepressureofsteam1MPaduringheataddition,and0.5MPaduringheatrejection.Thehighestpossibleefficiencyofthisheatengineis[a]6.2％[b]15.6％[c]50.0％[d]93.8％[e]100％5.2Aheatenginecycleisex555.3Aheatenginereceivesheatfromasourceat100℃andrejectsthewasteheattoasinkat50℃.Ifheatissuppliedtothisengineatarateof100kj/s,themaximumpowerthisheatenginecanproduceis[a]25.4kW[b]55.4kW[c]174.6kW[d]95.0kW[e]100.0kW5.3Aheatenginereceiveshea565.4Steamiscompressedfrom8MPaand300℃to10MPaisentropically.Thefinaltemperatureofthesteamis[a]290℃[b]300℃[c]320℃[d]330℃[e]340℃5.4Steamiscompressedfrom575.5Heliumgasiscompressedfrom1atmand25℃toapressureof10atmadiabatically.Thelowesttemperatureofheliumaftercompressionis[a]25℃[b]63℃[c]250℃[d]384℃[e]476℃5.5Heliumgasiscompressed585.6Steamexpandsinanadiabaticturbinefrom10MPaand500℃to0.1MPaatarateof8kg/s.Ifsteamleavestheturbineassaturatedvapor,thepoweroutputoftheturbineis[a]5586kw[b]698kw[c]2136kw[d]12,452kw[e]26,990kw5.6Steamexpandsinanadiaba595.7Aunitmassofasubstanceanirreversibleprocessfromstate1tostate2whilegainingheatfromthesurroundingsattemperatureTintheamountofq.Iftheentropyofthesubstanceisatstate1,andatstate2,theentropychangeofthesubstancesduringthisprocessis[a][b][c][d][e]5.7Aunitmassofasubstanc605.8Airiscompressedfromroomconditionstoaspecifiedpressureinareversiblemannerbytwocompressor:oneisothermalandtheotheradidbatic.Iftheentropychangeofairsduringthereversibleadiabaticcompression,thecorrectstatementregardingentropychangeofairperunitmassis[a][b][c][d][e]5.8Airiscompressedfromr615.9Heatislostthroughaplanewallsteadilyatarateof600W.Iftheinnerandoutersurfacetemperatureofthewallare20℃and5℃,respectively,therateofentropygenerationwithinthewallis[a]0.11W/K[b]4.21W/K[c]2.10W/K[d]142.1W/K[e]90.0W/K5.9Heatislostthroughapla625.10Airat15℃iscompressedsteadilyandisothermallyfrom100KPato700KPaatarateof0.12kg/s.Theminimumpowerinputtothecompressoris[a]1.0kW[b]11.2kW[c]25.8kW[d]19.3kW[e]16.1kW5.10Airat15℃iscompress635.11Airistobecompressedsteadilyandisentropicallyfrom1atmto16atmbyatwo-stagecompressor.Tominimizethetotalcompressionwork,theintermediatepressurebetweenthetwostagesmustbe[a]2atm[b]4atm[c]8atm[d]10atm[e]12atm5.11Airistobecompresseds645.12Liquidwaterentersanadiabaticpipingsystemat15℃atarateof5kg/s.Ifthewatertemperaturerisesby0.5℃duringflowduetofriction.therateofentropygenerationinthepipeis[a]36W/K[b]29W/K[c]685W/K[d]920W/K[e]8370W/K5.12Liquidwaterentersanad655.13Steamentersanadiabaticturbineat4MPaand500℃atarateof15kg/s,andexitsat0.2MPaand300℃.Therateofentropygenerationintheturbineis[a]0.8kW/K[b]1.2kW/K[c]12.0kW/K[d]15.1kW/K[e]17.4kW/K5.13Steamentersanadiabatic665.13Aquantityofairundergoesathermodynamiccycleconsistingofthreeprocessesinseries.Process1-2:constant-volumeheatingfromP1=0.1MPa,T1=288K,V1=0.02toP2=0.42MPa;Process2-3:constant-pressurecooling;Process3-1:isothermalheatingtotheinitialstate;EmployingtheidealgasmodelwithCp=1kJ/kgK,evaluatethechangeinentropyforeachprocess.Sketchthecycleonp-vcoordinates.5.13Aquantityofairundergoe67CHAPTER8THERMODYNAMICSOFHIGH-SPEEDGASFLOW8.1Inwhichmediumwillsoundtravelfastestforagiventemperature:air,helium,orargon?8.2Isitpossibletoaccelerateagastoasupersonicvelocityinaconvergingnozzle?8.3Airentersaconverging-divergingnozzleatapressureof1.2MPawithnegligiblevelocity.Whatisthelowestpressurethatcanbeobtainedatthethroatofthenozzle?CHAPTER88.1Inwhichmedium688.4Airentersanozzleat0.2MPa,350K,andavelocityof150m/s.Assumingisentropicflow,determinethepressureandtemperatureofairatalocationwheretheairvelocityequalsthevelocityofsound.Whatistheratiooftheareaatthislocationtotheentrancearea?8.5Airentersaconverging-divergingnozzleat0.8MPawithnegligiblevelocity.Assumingtheflowtobeisentropic,determinethebackpressurethatwillresultinanexitMachnumberofAirentersanozzleat0.269Airentersanadiabaticnozzleat800Kand140KPaandemergesat7KPa.Theisentropicefficiencyofthenozzleisknowntobe0.96.Determinethedischargevelocity.SketchtheprocessonaT-Sdiagramandlabelthestates.YoumayassumetheworkingfluidisaperfectgaswithCp=1kJ/kgK.Airentersanadiabati708.6Steamentersanconvergingnozzleat30.MPaand600℃withanegligiblevelocity,anditexitsat1.8MPa.Foranozzleexitareaof24c㎡,determinetheexit.Velocity,massflowrate,andexitMachnumberifthenozzle(a)isisentropicand(b)hasanefficiencyof90percent8.6Steamentersanconverging71CHAPTER9GASPOWERCYCLES9.1ACarnotcycleoperatesbetweenthetemperature