简介：Numericalsimulationsareperformedforlaminarnaturalconvectionheattransferfromacenteredconductingbodyenclosedinasquarecavity.Ahighaccuracyunsteadynumericalmethodisused,combiningtheuniqueconditionofthepressure,theconvergentsolutionsandthestream-functionvalueoftheinsideheat-conductingbodyaregivensimultaneously.Twoexamplesaresimulatedwiththisnumericalmethodandcomparedwiththeexperimentalresults.Theresultsofthenumericalsolutionsareconsistentwiththeexperimentalresults.Itshowsthatthenumericalmethodisvalidandfeasible.
简介：Fluidflowandheattransfercharacteristicsoutsideavibratingtubewerenumericallysimulatedbythedynamicmeshmethod.Themechanismofheattransferenhancementviaperiodicvibrationofthetubewasexploredbyusingthefieldsynergyprinciple.Itisfoundthatthefieldsynergyanglebetweenfluidvelocityvectorandtemperaturegradientvectorforaperiodicallyvibratingtubeissignificantlysmallerthanthatforastationarytube,anditchangesapproximatelyaccordingtothesinusoidallawinavibrationperiod.Theeffectoftimephaseofthevibrationonthefieldsynergyangleandconvectiveheattransfercoefficientwerealsodiscussed.Resultsindicatethatthevibrationcanenhanceheattransferandthiseffectismoreremarkablewhentimephaseanglerangesbetween50oand140oinahalfperiod.Especiallywhenthetimephaseangleis90o,theaveragefieldsynergyangleoutsidethetubereachestheminimum,whichleadstothebestheattransferperformance.
简介：Anumericalsimulationisperformedforthermalinstabilityandheattransferofviscoelasticfluidsinboundedporousmediaunderthebottomconstantheatfluxboundarycondition.Theresultsforsixdifferentcombinationsofrelaxationandretardationtimesdemonstratetheexistenceofthethermalinstabilityinducedflowbifurcation.Itisfoundthattheincreaseoftherelaxationtimecanenhancetheheattransferefficiencybydisturbingthefluidflowandfacilitatingthebifurcation.Theincreaseoftheretardationtimecanstabilizetheflowandpostponethebifurcation,leadingtosimplerflowpatternandlowerheattransferrate.
简介：Anexperimentalstudywascarriedouttoinvestigatetheinfluenceofdoubletwisted-tapeinserts(DTs)inmicro-fintubes(MFs)onheattransfer,frictionfactorandthermalperformancefactorcharacteristicsofthecompounddevicesinthefollowingconfigurations:(1)twistedtapesactedinthesamedirection(forco-swirl)whileMFandtwistedtapesactedinthesame(parallel)direction(MF-CoDTs:P),(2)twistedtapesactedinthesamedirection(forco-swirl)whilemicro-fintubeandtwistedtapesactedinoppositedirections(MF-CoDTs:O)and(3)twistedtapesactedinoppositedirectionsforcounterswirl(MF-CDTs).TheMFaloneandtheMFequippedwithasingletwistedtapeinparallel/oppositearrangementwerealsoconsideredforcomparison.TheexperimentswereconductedfortheflowswiththeReynoldsnumbersbetween5650and17000,underuniformheatfluxcondition.TheexperimentalresultsindicatethatMF-CDTsinducestrongerswirl/turbulenceflow,resultinginhigherheattransferrate,frictionfactorandthermalperformancefactorthanothercombineddevices.ThethermalperformancefactorsassociatedwiththeuseofMF-CDTswerefoundtobehigherthanthoseassociatedwiththeusesofMF-CoDTs:P,MF-CoDTs:OandMFaloneupto9.3%,6.5%and56.4%,respectively.TheempiricalcorrelationsdevelopedusingthepresentexperimentaldatafortheNusseltnumber,frictionfactorandthermalperformancefactorarealsoreported.
客服QQ：30444492琼网文【2021】1550-113号
增值电信业务经营许可证：琼B2-20210322
出版物经营许可证：新出发龙华出字第(2021)009号
广播电视节目制作经营许可证：(琼)字第00779号
版权所有 ©2002-2024 期刊网(www.qikanchina.com) 琼ICP备2021005105号
