分形树状通道换热器内的流动换热特性

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1、第31卷第3期航空学报V01．31No．32010年3月ACTAAERONAUTICAETASTRONAUTICASINICAMar．2010文章编号：1000—6893(2010)03—0472—08分形树状通道换热器内的流动换热特性陈永平，杨迎春，施明恒，吴嘉峰(东南大学能源与环境学院，江苏南京210096)CharacteristicsofHeatandFluidFlowinFractalTree-likeChannelHeatSinkChenYongping。YangYingchun，ShiMingheng，WuJiafeng(SchoolofEnergyandEnvironmen

2、t，SoutheastUniversity，Nanjing210096，China)摘要：建立了分形树状通道换热器中层流流动与传热的三维稳态模型，采用流固耦合计算方法对人口水力直径为4mm的矩形截面树状通道内流动换热进行了数值模拟，重点研究了分叉效应对传热的强化机理和换热器受热面的温度分布。研究结果表明：分叉处形成的二次流能有效地强化换热；与传统的蛇形通道相比，分形树状通道换热器具有温度均匀性好、压降小的明显优势。在相同入口雷诺数时，分形树状通道换热器受热面的最大温差远小于蛇形通道换热器，另外，分形树状通道的层流流动压降较之蛇形流道可减小50％以上。同时，加工了分形树状通道换热器及蛇形通道

3、换热器各一套，对数值模拟结果进行了实验验证。实验值与模拟值能较好地吻合，证明了所建流动换热三维数值模型正确可信。关键词：分形；换热器；流动；传热；均温性中图分类号：V211．3；TKl24文献标识码：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