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1、第31卷第3期航空學報V01.31No.32010年3月ACTAAERONAUTICAETASTRONAUTICASINICAMar.2010文章編號:1000—6893(2010)03—0472—08分形樹狀通道換熱器內(nèi)的流動換熱特性陳永平,楊迎春,施明恒,吳嘉峰(東南大學能源與環(huán)境學院,江蘇南京210096)CharacteristicsofHeatandFluidFlowinFractalTree-likeChannelHeatSinkChenYongping。YangYingchun,ShiMingheng,WuJiafeng(SchoolofEnergyandEnvironmen
2、t,SoutheastUniversity,Nanjing210096,China)摘要:建立了分形樹狀通道換熱器中層流流動與傳熱的三維穩(wěn)態(tài)模型,采用流固耦合計算方法對人口水力直徑為4mm的矩形截面樹狀通道內(nèi)流動換熱進行了數(shù)值模擬,重點研究了分叉效應對傳熱的強化機理和換熱器受熱面的溫度分布。研究結(jié)果表明:分叉處形成的二次流能有效地強化換熱;與傳統(tǒng)的蛇形通道相比,分形樹狀通道換熱器具有溫度均勻性好、壓降小的明顯優(yōu)勢。在相同入口雷諾數(shù)時,分形樹狀通道換熱器受熱面的最大溫差遠小于蛇形通道換熱器,另外,分形樹狀通道的層流流動壓降較之蛇形流道可減小50%以上。同時,加工了分形樹狀通道換熱器及蛇形通道
3、換熱器各一套,對數(shù)值模擬結(jié)果進行了實驗驗證。實驗值與模擬值能較好地吻合,證明了所建流動換熱三維數(shù)值模型正確可信。關(guān)鍵詞:分形;換熱器;流動;傳熱;均溫性中圖分類號:V211.3;TKl24文獻標識碼:AAbstract:Athree—dimensional(3D)steadymodelforheattransferandlaminarfluidflowinfractaltree—likechannelheatsinkisdeveloped.Thelaminarconvectiveheattransferinthefractaltree-likechannelheatsinkwithanin
4、lethydraulicdiameterof4mmforrectangularcross—rsectionisnumericallysimulatedbyliquid—。solidcouplingnumericalmethod.ThesignificantheattransferenhancementmechanismbythebifurcationsandthetemperaturedistributiononheatingSUrfaceisdiscussedindetail.Theresultsindicatethatthesecondaryflowmotiongeneratedatb
5、ifurcationscaneffeetivelyenhanceheattransfer.Fractaltree-likechannelheatsinkhasobviousadvantagesoverthetraditionalserpentineflowpatterninbothheattransferandpressuredrop.UnderthesameinletReynoldsnumber,themaximumtemperaturedifferenceonthesurfaceoffractaltreelikechan-nelheatsinkisfarlessthanthatofse
6、rpentineflowpattern;thepressuredropoflaminarfluidflowinfractaltree-likechannelislessthanthatinserpentinechannelbyover50%.Inaddition,afractaltree-likechannelheatsinkandaserpentinechannelheatsinkarerespectivelydesignedandfabricatedtOconducttheverificationexperimentfornumericalsimulation.Thetemperatu
7、redistributionandpressuredropmeasuredbyexperimentareinagoodagreementwiththoseobtainedbynumericalsimulation,whichverifiesedthattheproposed3Dmodelisreliable.Keywords:fractal;heatsink;fluidflow;heattransfer;temperat