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ID:40357956
大小:65.24 KB
页数:6页
时间:2019-07-31
《Flow Boiling Heat Transfer Coefficient In Minichannels – Correlation and Trends》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、FlowBoilingHeatTransferCoefficientInMinichannels–CorrelationandTrendsSatishG.KandlikarMarkE.SteinkeMechanicalEngineeringDepartment,RochesterInstituteofTechnology,Rochester,NewYork14623,USATheflowboilingheattransferinsmalldiameterpassagesisbeingappliedinmanyadvanceddesigns,includingelect
2、ronicscooling,fuelcellheatexchangers,andotherhighheatfluxdissipationapplications.Anumberofstudiesareavailableinliteraturecomparingflowpatternsinminichannelstothoseobservedinconventionalchannels.Thepresentstudyisfocusedoncomparingtheflowboilingheattransfercoefficientwiththecorrelationsde
3、velopedforconventionalchannels.ItisfoundthattheKandlikar(1990)correlationdevelopedforconventionaldiametertubesisapplicableforminichannelsaswell.Thetrendsintheheattransfercoefficientwithqualityarealsofoundtobesimilartotheconventionaldiametertubes.Onenotabledifferencebeingtheuseoflaminarf
4、lowequationforsinglephaseliquidonlyheattransfercoefficientatRebelow1500-2300forsmalldiametertubes.1.Introduction2Theneedtodissipateheatfluxeshigherthanthosecustomarilyhandledbyaircooling(10-20W/cm)isforcingthethermaldesignertoconsidersingle-phaseliquidcoolingasanoption.Thenextstepinthis
5、directionisexpectedtobephasechangecooling,utilizingflowboilingofarefrigerantinsmalldiameterpassages.Heatpipes,fuelcells,advancedcompactevaporators,allutilizechanneldimensionsthatareontheorderof1mmhydraulicdiameter.Theclassificationofchannelsbasedonthehydraulicdiameterposesconsiderablech
6、allengesasthesechannelsareusedinallthreemodesofheattransfer:single-phase,evaporationandcondensation.Thecriteriaforsuchclassificationarequitedifferentforeachoftheprocesses.Inthesingle-phaseapplication,comparisonwiththeintermoleculardistancesmakesperfectsense.Inflowboilingandcondensationa
7、pplication,thebubblediameteranddropletdiametersrespectivelyhaveaphysicalsignificance.However,forthesakeofuniformity,itisdesirabletohaveaclassificationschemethatisindependentoftheheattransferprocessoccurringinsidethechannels.Withthisinmind,thefollowingclassificationbaseduponhydr
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