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1、Int.J.HeatMassTransJbr.Vol.38,No.1,pp.15:%161,1995Copyright?1994ElsevierScienceLtdPergamonPrintedinGreatBritain.Allrightsreserved0017-9310/95$9.50+0.000017-9310(94)E0107-6Free-convectiveheattransferonaverticalsurfacewithheat-fluxdiscontinuityV.S.BURAK,S.V.VOLKOV,O.G.MARTYNENKO,P.P.K
2、HRAMTSOVandI.A.SHIKHLuikovHeatandMassTransferInstitute,AcademyofSciencesofBelarus,Minsk220072,Belarus(Received27July1993)Al~traet--Thecharacteroffree-convectiveflownearaverticalplatewithaheat-fluxjumponthesurfaceisstudiedexperimentally.Twocasesofplatespatialorientationareinvestigate
3、d.Thetemperaturefieldismeasuredandthevelocityfieldisvisualizedinthefree-convectiveflownearasurface.Forthecaseofahigherheatfluxfromthelowerportionoftheplate,achangeisnotedinthecharacterofthetemperatureprofileinaboundarylayerintheplateupperportionascomparedwiththeconstantheatfluxsurfa
4、ce.Theshiftofatemperaturelocalmaximuminaboundarylayertosomedistancefromthesurfaceintothefluxdepthisrevealed.Forthecaseofalargedensityofheatliberationattheinitialstageoffree-convectiveflowformation,theappearanceofatwo-dimensionalvortex,originatingfromtheinteractionoftheheatedairfloww
5、ithmotionlesscoolerairintheupperportionoftheplate,isfound.INTRODUCTIONwhichfreeconvectioninairnearaverticalsurfacewithlocalizedheatsourceswasexperimentallyinves-Atpresentinthescientificliteraturethereareagreattigatedbasedoninterferometricmethodsandthevel-numberofpapersdevotedtothest
6、udyoffreecon-ocityfieldinaliquidboundarylayerwasvisualizedvectionnearanonuniformlyheatedverticalsurface.bysmokeaswell.Inref.[11]theprocessesofheatAmongthefirstpublicationsdealingwiththisprob-transferfromalocalheatsourceplacedinthelowerlemref.[l]shouldbementionedinwhichtheauthorsport
7、ionofanadiabaticinsulatedsurfacewerestudied.measuredthetemperature-fieldprofileusingpos-Temperaturefieldswereinvestigatedbyacopper-itionedthermocouples.Theoreticalstudiesoffreecon-constantanthermocouple.vectionstartedbyPohlhausenweresuccessfullycon-Inthepresentpaper,usingopticalmeth
8、ods,thetinuedinwork