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1、InternationalJournalofRefrigeration27(2004)876–883www.elsevier.com/locate/ijrefrigExperimentswithmicro-?ntubeinsinglephaseJacquelineBianconCopetti*,MarioHenriqueMacagnan,DaianadeSouza,RejaneDeCe′saroOliveskiDepartmentofMechanicalEngineering,SchoolofPhysicalandTechno

2、logicalSciences,UniversidadedoValedoRiodosSinos,Av.Unisinos,950Sa?oLeopoldo,RS93022-000BrazilReceived4July2003;receivedinrevisedform30December2003;accepted2April2004AbstractThisworkshowsheattransferandfrictioncharacteristicsforwatersingle-phase?owinmicro-?ntubes.The

3、analysisofthermalandhydraulicbehaviorfromalaminartoaturbulent?owwascarriedoutinanexperimentalsetupwitha9.52mmdiametermicro-?ntube.Thetubewaswrappedupwithanelectricalresistancetapetosupplyaconstantheat?uxtoitssurface.Differentoperationalconditionswereconsideredintheh

4、eatingtests.Theinletandoutlettemperatures,differentialwalltemperaturesalongthetube,pressuredropand?owrateweremeasured.Therelationshipsofheat?uxand?owratewithheattransfercoef?cientandpressuredropwereanalyzed.Underthesameconditions,comparativeexperimentswithaninternal

5、lysmoothtubewereconducted.Themicro-?ntubeprovideshigherheattransferperformancethanthesmoothtube(inturbulent?owhmicro-fin=hsmooth?2:9).InspiteoftheincreaseinpressuredropeDpmicro-fin=Dpsmooth?1:7Ttheheattransferresultsweresigni?cantlyhigher(about80%).Thisshowstheadvan

6、tagesofthisenhancedcon?gurationinthermalperformancerelatedtoconventionaltubes.ThesmoothtuberesultswerevalidatedbythecomparisonwiththeDittus–BoelterandGnielinskicorrelations.Forthemicro-?ntubeanempiricalcorrelationtotheheattransfercoef?cientadjustedfromthesetofmeasur

7、eddataisproposed.Thevaluesobtainedareinconformitywithexperimentalresults.q2004ElsevierLtdandIIR.Allrightsreserved.Keywords:Experiment;Heattransfer;Pressuredrop;Flow;Water;FinnedtubeTubeamicroailetlesa`e′coulementmonophasique:expe′riencesMots-cle′s:Expe′rimentation;T

8、ransfertdechaleur;Chutedepression;Ecoulement;Eau;Tubeailete′1.Introductionsmalldiameterwereintroducedforthe?rsttimeintheendofthe1970sbyHit