Therefore,theheattransferrateifcalculatedfrom:（）whereisthemassflowrate,Ti,ToandTsaretheinlet,outletandsurfacetemperatures,respectively,QhAs(TseTm)istheheattransferrate,Tmisthemeanflowtemperatureovertheheattransferarea,As,andεistheheatexchangereffectiveness,calculatedfrom(KaysandLondon,):（）whereNTUhAs/mcpisthenumberoftransferunits.Thepressuredrop,ontheotherhand,canbecalculatedfrom(KaysandLondon,):（）walledthermodynamicdesignmethod,laterrenamedasentropygenerationminimizationmethod(Bajan,),whichbalancesthethermodynamicirreversibilitiesduetotheheattransferwithafinitetemperaturedifferencetothoseassociatedwiththeviscousfluidflow,thusprovidingand-lawcriterionthathasbeenwidelyusedforthesakeofheatexchangerdesignandoptimization(SanandJan,；Leprousetal.,；AchaeanandWongwises,；Mishapetal.,；Kotciogluetal.,；Pussolietal.,；Hermesetal.,).However,themodelsadoptedinthosestudiesdonotprovideastraightforwardindicationofhowthedesignparameters(geometry,fluidproperties,workingconditions)affecttherateofentropygeneration.Theyalsorequirecomplexnumericalsolutions,beingthereforenotsuitableforback-of-the-envelopecalculationsintheindustrialenvironment.Inarecentpublication,Hermes()advancedanexplicit,algebraicformulationwhichexpressesthedimensionlessrateofentropygenerationasafunctionofthenumberoftransferunits,thefluidproperties,thethermalhydrauliccharacteristics(jandfcurves),andtheoperating.conditions(heattransferduty,corevelocity,andcoilsurfacetemperature)forheatexchangerswithuniformwalltemperature.Anexpressionfortheoptimumheatexchangereffectiveness,basedontheworkingconditions,heatexchangergeometryandfluidproperties,wasalsopresented.ThepresentpaperisthereforeaimedatassessingtheformulationintroducedbyHermes()fordesigningcondensersandevaporatorsforrefrigerationsystemsspanningfromhouse-holdapplication,whichamountswoftheelectricalenergyconsumedworldwide(MaloandSilva,)..MathematicalformulationIngeneral,condensersandevaporatorsforrefrigerationapplicationsaredesignedconsideringthecoilfloodedwithtwo-phaserefrigerant,andalsoawalltemperatureequaltotherefrigeranttemperature(BarbarossaandHermes,),insuchawayasthetemperatureprofilesalongthestreamsarethoserepresentedinFig..Inaddition,theouter(e.g.,air,water,brine)sideheattransfercoefficientandthephysicalpropertiesareassumedtobeconstant.Therefore,theheattransferrateifcalculatedfrom:（）whereisthemassflowrate,Ti,ToandTsaretheinlet,outletandsurfacetemperatures,respectively,QhAs(TseTm)istheheattransferrate,Tmisthemeanflowtemperatureovertheheattransferarea,As,andεistheheatexchangereffectiveness,calculatedfrom(KaysandLondon,):（）whereNTUhAs/mcpisthenumberoftransferunits.Thepressuredrop,ontheotherhand,canbecalculatedfrom(KaysandLondon,):（）w流体性质与温度无关。每种流体这些特性数值以平均流体温度来指定，并且作为输入数据。冷热流体入口温度作为数值分析边界条件。板式换热器通道中流体无量纲传热系数可看成是与热传递相关一种类型(Raoetal.,)：()ShahandFocke()进行了实验研究板式换热器热传递和压降特性。他们注意到，常数C取决于换热板类型和换热器几何形状，而常数n取决于流体流态。Edwardsetal.()研究证明得出，在雷诺数大约小于时，实验数据是以标绘，而不是APVJuniorParaflow板落在表明典型传热关系坡度线/处Re值：在雷诺数较高时（Re大于），坡度约为.，这样会得出过度条件和湍流条件：这种关系也可能成为相互距离b两个平行板之间湍流类型。可假设为，由于板褶皱，取决于当量直径雷诺数会影响热传递增加。对于牛顿流体，Edwardsetal得到结果，表明APVJuniorParaflow板被作为流动通道，并可以推广到任何板类型，提供常数C来作为修正值。Mehrabian(年)进行了广泛研究，从实验和理论观点探究流体动力学和板式换热器热性能。在湍流（Re大于）条件下，他对APVSR板提出了以下关系：等式（）同时适用于板式换热器冷热流体通道，传热系数分别为和h，轴截面j总传热系数是：()()正如Edwardsetal所提出，在雷诺数低至情况，板式换热器流动通道中流体也可能形成湍流。因此，湍流假设分析是合理，并且等式（）适用于水为介质热流体，同时甘油、苯和辛烷可作为冷流体。这些冷流一定要选择其粘度随温度而变化。结果和讨论为了得到独立网格数据结果，程序运行时将轴向分为几个不同部分。将确定网格点数值结果与相应(Haseleretal.,)实验结果进行对比，然后记录两者之间差值。值得注意是，增加网格点数量会减少差值。然而，当轴向部分数目是时候，此时可产生最小差值，当超过时，差值减小并不明显。通过实验结果表明，轴向部分数目为。而，,,这些数字都是倍数。这是在(Haseleretal.,).中对比相应点处实验结果目。应该被提及是，在获得数值解之初，两种流体出口温度并不清楚，可通过两者进口平均温度来估算。当得到出口温度时，每种流体性质可以由其本身平均温度来估算。(Khoramabadi,).换热板尺寸和和流体流动条件数值分析列于表.这些数值都是(Haseleretal.,)中用于试验温度测量所需尺寸和条件。水典型温度实验温度列于表II，以当量直径热流体和冷流体雷诺数分别是和。换热器中间通道局部温度数据结果然后与V型区域实验温度相比较，列于表II并得到数值上一致。这种误差在范围内，这样才表明这种数值法准确性。由于数值计算程序已经被验证，进口冷热流体之间变大温度差会使流体粘度显著影响温度分布、总传热系数和换热器传热性能。冷流体和热流体进口温度分别是这个程序适用于水-水、水-苯、水-异辛烷四种类型流体。冷热流体沿换热器温度分布如图和。水-苯与水-苯温度分布相似，因此，并没有在图和中。对于每种类型工作流体，恒定和变化流体粘度温度分布都有所体现。可以注意到，水之间温度分布误差大于甘油和异辛烷之间误差。然而，随着温度改变，水粘度变化比甘油和异辛烷较为强烈。这种现象原因是甘油和异辛烷对流传热系数小于水之间对流传热系数，因此，它们控制了总传热系数。表板尺寸和流动细节表数值比较和实验结果图冷流体沿流动通道温度分布图热流体沿流动通道温度分布图总传热系数与冷流体温度之间关系图总传热系数与热流体温度之间关系图和图分别描绘出了总传热系数与冷热流体之间变化关系。然而，当假设流体粘度不变时，总传热系数也是不变。这样使得粘度变化是控制总传热系数一个重要因素。U与T之间线性关系和液体粘度与温度关系都在图中体现。表中，在在温度范围内粘度显示出了线性变化关系。然而，这种现象并不违背大多数流体以指数函数与温度之间作为标准。热流体和冷流体传热系数随温度线性变化分别在图和图中。换热器恒定粘度和多变粘度关系图在图中。此图是表示水与异辛烷之间关系。然而水-水、水-苯和水-甘油都有相似图形。换热器性能并不因温度控制下粘度影响。当粘度只受温度限制时，对于不同工作流体图描绘了图形。只要NTU很小（NTU），换热器性能就会因不同流体而改变。与图和图有关性能计算基于NTU和U定义：整合起来可以为：()()图粘度随流体温度变化图热端传热系数与热流体温度之间关系图冷端传热系数与冷流体温度关系图可变U对水-异辛烷中ε-NTU影响图流体种类对可变Uε-NTU影响alledthermodynamidesignmethod,laterrenamedasentropygenerationminimizationmethod(Bajan,),whichbalancesthethermodynamicirreversibilitiesduetotheheattransferwithafinitetemperaturedifferencetothoseassociatedwiththeviscousfluidflow,thusprovidingand-lawcriterionthathasbeenwidelyusedforthesakeofheatexchangerdesignandoptimization(SanandJan,；Leprousetal.,；AchaeanandWongwises,；Mishapetal.,；Kotciogluetal.,；Pus附录B：参考英文文献及译文Thermodynamicdesignofcondensersandevaporators:FormulationandapplicationsChristianJ.L.HermesabstractThispaperassessesthetherm-hydraulicdesignapproachintroducedinapreviouspublication(Hermes,)forcondensersandevaporatorsaimedatminimumentropygeneration.Analgebraicmodelwhichexpressesthedimensionlessrateofentropygenerationasafunctionofthenumberoftransferunits,thefluidproperties,thethermal-hydrauliccharacteristics,andtheoperatingconditionsisderived.Casestudiesarecarriedoutwithdifferentheatexchangerconfigurgitationsforsmall-capacityrefrigerationapplications.Thetheoreticalanalysisledtotheconclusionthatahigheffectivenessheatexchangerdoesnotnecessarilyprovidethebestthermal-hydraulicdesignforcondenserandevaporatorcoils,whentheratesofentropygenerationduetoheattransferandfluidfrictionareofthesameorderofmagnitude.Theanalysisalsoindicatedthatahighaspectratioheatexchangerproducesaloweramountofentropythanalowaspectratioone.Conceptionthermodynamiccondenseretdesseevaporate:formulationetapplications.Keywords:floatinghead；heatexchanger；design；industry.IntroductionCondensersandevaporatorsareheatexchangerswithfairlyuniformwalltemperatureemployedinawiderangeofHVACRproducts,spanningfromhouseholdtoindustrialapplications.Ingeneral,theyaredesignedaimingataccomplishingacertainheattransferdutyatthepenaltyofpumpingpower.Therearetwowell-establishedmethodsavailableforthethermalheatexchangerdesign,thelog-meantemperaturedifference(LMTD)andtheeffectiveness/numberoftransferunits(ε-NTU)approach(KakacandLiu,；ShahandSiliculose,).Thesecondhasbeenpreferredtotheformerforthesakeofcompactheatexchangerdesignastheeffectiveness(ε),definedastheratiobetweentheactualheattransferrateandthemaximumamountthatcanbetransferred,providesast-lawcriteriontoranktheheatexchanger.performance,whereasthenumberoftransferunits(NTU)comparesthethermalsizeoftheheatexchangerwithitscapacityofheatingorcoolingfluid.Furthermore,theε-NTUapproachavoidsthecumbersomeiterativesolutionrequiredbytheLMTDforoutlettemperaturecalculations.Nonetheless,neitherε-NTUorLMTDapproachesaresuitabletoaddresstheheattransfer/pumpingpowertrade-off,whichisthecruxforabalancedheatexchangerdesign.Forthispurpose,Bajan()establishedtheso-calledthermodynamicdesignmethod,laterrenamedasentropygenerationminimizationmethod(Bajan,),whichbalancesthethermodynamicirreversibilitiesduetotheheattransferwithafinitetemperaturedifferencetothoseassociatedwiththeviscousfluidflow,thusprovidingand-lawcriterionthathasbeenwidelyusedforthesakeofheatexchangerdesignandoptimization(SanandJan,；Leprousetal.,；AchaeanandWongwises,；Mishapetal.,；Kotciogluetal.,；Pussolietal.,；Hermesetal.,).However,themodelsadoptedinthosestudiesdonotprovideastraightforwardindicationofhowthedesignparameters(geometry,fluidproperties,workingconditions)affecttherateofentropygeneration.Theyalsorequirecomplexnumericalsolutions,beingthereforenotsuitableforback-of-the-envelopecalculationsintheindustrialenvironment.Inarecentpublication,Hermes()advancedanexplicit,algebraicformulationwhichexpressesthedimensionlessrateofentropygenerationasafunctionofthenumberoftransferunits,thefluidproperties,thethermalhydrauliccharacteristics(jandfcurves),andtheoperating.conditions(heattransferduty,corevelocity,andcoilsurfacetemperature)forheatexchangerswithuniformwalltemperature.Anexpressionfortheoptimumheatexchangereffectiveness,basedontheworkingconditions,heatexchangergeometryandfluidproperties,wasalsopresented.ThepresentpaperisthereforeaimedatassessingtheformulationintroducedbyHermes()fordesigningcondensersandevaporatorsforrefrigerationsystemsspanningfromhouse-holdapplication,whichamountswoftheelectricalenergyconsumedworldwide(MaloandSilva,)..MathematicalformulationIngeneral,condensersandevaporatorsforrefrigerationapplicationsaredesignedconsideringthecoilfloodedwithtwo-phas        附录B：参考英文文献及译文Thermodynamicdesignofcondensersandevaporators:FormulationandapplicationsChristianJ.L.HermesabstractThispaperassessesthetherm-hydraulicdesignapproachintroducedinapreviouspublication(Hermes,2012)forcondensersandevaporatorsaimedatminimumentropygeneration.Analgebraicmodelwhichexpressesthedimensionlessrateofentropygenerationasafunctionofthenu

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