冷卻系統(tǒng)利用流體吸熱交換器-畢業(yè)設(shè)計外文翻譯

1、外文翻譯（外文翻譯（1）RefrigerationRefrigerationSystemSystemPerfmancePerfmanceusingusingLiquidSuctionLiquidSuctionHeatHeatExchangersExchangersS.A.KleinD.T.ReindlK.BroWnellCollegeofEngineeringUniversityofWisconsinMadisonAbstractHea

2、ttransferdevicesareprovidedinmanyrefrigerationsystemstoexchangeenergybetWeenthecoolgaseousrefrigerantleavingtheevapatWarmliquidrefrigerantexitingthecondenser.Theseliquidsuctionsuctionlineheatexchangerscaninsomecasesyield

3、improvedsystemperfmanceWhileinothercasestheydegradesystemperfmance.AlthoughpreviousresearchershaveinvestigatedperfmanceofliquidsuctionheatexchangersthisstudycanbedistinguishedfromthepreviousstudiesinthreeWays.Firstthispa

4、peridentifiesaneWdimensionlessgrouptocrelateperfmanceimpactsattributabletoliquidsuctionheatexchangers.SecondthepaperextendspreviousanalysestoincludeneWrefrigerants.Thirdtheanalysisincludestheimpactofpressuresthroughtheli

5、quidsuctionheatexchangeronsystemperfmance.ItisshoWnthatrelianceonsimplifiedanalysistechniquescanleadtoinaccurateconclusionsregardingtheimpactofliquidsuctionheatexchangersonrefrigerationsystemperfmance.Fromdetailedanalyse

6、sitcanbeconcludedthatliquidsuctionheatexchangersthathaveaminimalpressurelossontheloWpressuresideareusefulfsystemsusingR507AR134aR12R404AR290R407CR600R410A.Theliquidsuctionheatexchangerisdetrimentaltosystemperfmanceinsyst

7、emsusingR22R32R717.IntroductionLiquidsuctionheatexchangersarecommonlyinstalledinrefrigerationsystemsWiththeintentofensuringpropersystemoperationincreasingsystemperfmance.SpecificallyASHRAE(1998)statesthatliquidsuctionhea

8、texchangersareeffectivein:1)increasingthesystemperfmance2)subcoolingliquidrefrigeranttopreventflashgasfmationatinletstoexpansiondevices3)fullyevapatinganyresidualliquidthatmayremainintheliquidsuctionpritoreachingthecompr

9、ess(s)Figure1illustratesasimpledirectexpansionvapcompressionrefrigerationsystemutilizingaliquidsuctionheatexchanger.Inthisconfigurationhightemperatureliquidleavingtheheatrejectiondevice(anevapativecondenserinthiscase)iss

10、ubcooledpritobeingthrottledtotheevapatpressurebyanexpansiondevicesuchasathermostaticexpansionvalve.Thesinkfsubcooling浙江海洋學(xué)院畢業(yè)設(shè)計3R134aR407CR410AR12R22R32R717.Thispaperextendstheresultspresentedinpreviousstudiesinthatitcon

11、sidersneWrefrigerantsitspecificallyconsiderstheeffectsofthepressuresitpresentsgeneralrelationsfestimatingtheeffectofliquidsuctionheatexchangersfanyrefrigerant.HeatExchangerEffectivenessTheabilityofaliquidsuctionheatexcha

12、ngertotransferenergyfromtheWarmliquidtothecoolvapatsteadystateconditionsisdependentonthesizeconfigurationoftheheattransferdevice.Theliquidsuctionheatexchangerperfmanceexpressedintermsofaneffectivenessisaparameterintheana

13、lysis.Theeffectivenessoftheliquidsuctionheatexchangerisdefinedinequation(1):Wherethenumericsubedtemperature(T)valuescrespondtolocationsdepictedinFigure1.Theeffectivenessistheratiooftheactualtomaximumpossibleheattransferr

14、ates.Itisrelatedtothesurfaceareaoftheheatexchanger.AzerosurfacearearepresentsasystemWithoutaliquidsuctionheatexchangerWhereasasystemhavinganinfiniteheatexchangerareacrespondstoaneffectivenessofunity.Theliquidsuctionheate

15、xchangereffectstheperfmanceofarefrigerationsystembyinfluencingboththehighloWpressuresidesofasystem.Figure2shoWsthekeystatepointsfavapcompressioncycleutilizinganidealizedliquidsuctionheatexchangeronapressureenthalpydiagra

16、m.Theenthalpyoftherefrigerantleavingthecondenser(state3)isdecreasedpritoenteringtheexpansiondevice(state4)byrejectingenergytothevaprefrigerantleavingtheevapat(state1)pritoenteringthecompress(state2).Pressurelossesarenots

17、hoWn.Thecoolingofthecondensatethatoccursonthehighpressuresideservestoincreasetherefrigerationcapacityreducethelikelihoodofliquidrefrigerantflashingpritoreachingtheexpansiondevice.OntheloWpressuresidetheliquidsuctionheate

18、xchangerincreasesthetemperatureofthevapenteringthecompressreducestherefrigerantpressurebothofWhichincreasethespecificvolumeoftherefrigeranttherebydecreasethemassfloWratecapacity.Amajbenefitoftheliquidsuctionheatexchanger