硕士论文-并联型水冷散热器

并联型水冷散热器的数值模拟及优化重庆大学硕士学位论文（学术学位）学生姓名：邹羽指导教师：李隆键教授专业：动力工程及工程热物理学科门类：工学重庆大学动力工程学院二O一六年五月NumericalSimulationandOptimizationoftheParallelChannelWaterCoolingRadiatorAThesisSubmittedtoChongqingUniversityinPartialFulfillmentoftheRequirementfortheMaster’sDegreeofEngineeringByYuZouSupervisedbyProf.LongjianLiSpecialty:PowerEngineering&EngineeringThermophysicsCollegeofPowerEngineeringChongqingUniversity,Chongqing,ChinaApril,2016中文摘要I摘要随着我国经济的不断发展，特别是高铁行业的飞速发展，各种电力电子设备在动力机车上得到了越来越广泛的应用，特别是大功率的IGBT模块成为了高速动车组上越来越重要的组件。这些电力电子设备正朝着大功率、小型化、集成化、高性能的方向不断发展。随之而来的问题就是，这些设备的发热量越来越大，致使系统的热流密度剧增。而这些设备必须在一定温度范围内才能正常工作，若温度过高超过其所允许工作的最高温度，会致使设备的可靠性大幅降低甚至烧坏设备。因此，对动力机车上的电力电子设备的散热研究变得越来越重要。目前，动力机车上所用的散热器以水冷散热器为主，传统的水冷散热器大多采用串联型流道，它存在的问题就是：在沿着流动的方向，冷却水的温度是不断升高的，造成整个散热器的温度分布很不均匀。为了解决上述问题，本课题将研究一种并联型流道的水冷散热器，主要工作内容如下：①建立了并联型水冷散热器的物理数学模型，并进行了相应的数值模拟计算，得到了衡量散热器性能的各个相关参数，并对计算结果进行了分析。提出了衡量温度分布均匀性的方法，并通过分析得出了：流量分布的均匀性决定了温度分布的均匀性。然后，比较了不同的进口冷却水流量对散热器性能的影响。结果表明，散热器温度分布的均匀性是随着流量增大先增加后减小，存在一个临界流量值使温度分布最均匀。②由于水冷散热器的完整模型结构相对复杂，网格数量巨大，为了减少计算量和缩短计算时间，提出了一种有效的简化模型分析方法，并对模型的可行性进行了验证。③为了提高水冷散热器的综合性能和温度、流量分布均匀性，对其进行了结构优化，设计了平板型、平直翅片型、扰流柱型和折流型四种不同的流道结构，对四种流道结构进行了数值模拟计算，得到了每种结构的阻力与传热性能，并考察了流道厚度对散热性能的影响。通过散热器的综合性能评价因子对每种结构的散热器进行了分析，结果表明折流型流道的综合性能是最好的。④运用多孔介质模型分析了散热器在每种流道结构下的流量分布均匀性，结果表明折流型散热器的流量和温度分布均匀性是最好的。关键词：并联型水冷散热器，IGBT，数值模拟，综合性能评价因子，温度均匀性重庆大学硕士学位论文II英文摘要IIIABSTRACTWitheconomicboomofChina,especiallytherapiddevelopmentofhigh-speedrailindustry,variouspowerelectronicdeviceshavebeenappliedmoreandmorewidelytolocomotives.Particularly,high-powerIGBTmoduleshavealreadybecomeincreasinglysignificantinhigh-speedrail.Allthesepowerelectronicdevicesdeveloptowardthehigh-power,miniaturization,integrationandhigh-performancedirection.Theproblemfollowingitisthattheincreasingcalorificvalueofthesedevicesrendersthatheatfluxofsystemalsoincreasesquickly.However,thisequipmenthastoworkatacertaintemperaturerange.Ifthetemperatureexceedsthemaximumallowableworkingtemperature,thereliabilityoftheequipmentmaybedramaticallyreducedandeventheequipmentbeburneddown.Asaresult,thestudyoncoolingthedevicesinlocomotiveshasbecomenecessarilysignificant.Atpresent,thewater-coolingradiatorhaspredominatedinlocomotives.Channelsintraditionalwater-coolingradiatorsaremostlyconnectedinseries.Theproblemisthatthetemperatureofcoolingwaterwillcontinuetorisealongtheflowdirection,whichwillresultinunevendistributionoftemperatureontheradiator.Inordertodealwithabove-describedproblem,thispaperfocusesonthewater-coolingradiatorwhosechannelsareconnectedinparallel.Themaincontentsofthispaperareasfollows:①Physicalandmathematicmodeloftheparallelwater-coolingradiatorhasbeenestablishedandnumericalsimulationwasappliedtothemodel.Then,variousparametersoftheperformanceoftheradiatorwereobtainedandthecalculatedresultswereanalyzed,too.Amethodformeasuringtheuniformityoftemperaturedistribution,whichisdeterminedbytheuniformityofflowdistribution,hasbeenproposed.Moreover,bycomparingdifferentflowrateofthecoolingwater,itwasconcludedthattheuniformityoftemperaturedistributionwouldfirstincreaseandthendecreaseasflowrateincreaseandthereexistsacriticalflowratethatcanmakethetemperatureuniformityachievetheoptimalvalue.②Becauseofthesophisticationoftheradiator’smodelandhugegrid,aneffectivesimplifiedmodelmethodhasbeenproposedtoreducethecomputationcostandshortencomputationtime.Inaddition,thefeasibilityofthemodelhasbeenverified.③Inordertoimprovetheperformanceandtemperatureandflowrateuniformityoftheradiator,structureoptimizationiscarriedout.Fourdifferentchannelstructures,重庆大学硕士学位论文IVincludingtheplate,straight-finned,pin-finsandzigzagchannel,weredesigned.Frictionalandheattransfercharacteristicsofeverystructurewereobtainedbyapplyingnumericalsimulationtothem.Theeffectofflowchannel’sthicknessoncoolingperformancewasalsoinvestigated.Fourkindsofradiatorswereanalyzedwiththeoverallperformanceevaluationfactor.Theresultsshowthatthecomprehensiveperformanceofthezigzagchannelisoptimal.④Theflowdistributionuniformityofeverychannelstructureoftheradiatorhasbeenanalyzedbyusingtheporousmediamodel,whichshowsthattheuniformityoftemperatureandflowdistributionofthezigzagradiatorisoptimal.Keywords：ParallelChannelWaterCoolingRadiator,IGBT,NumericalSimulation，OverallPerformanceEvaluationFactor,TemperatureUniformity目录V目录中文摘要..........................................................................................................................................I英文摘要.......................................................................................................................................III1绪论.........................................................................................................................................11.1课题背景...................................................................................................................................11.2电力电子设备主要散热方法...................................................................................................21.3动力机车水冷散热系统介绍..................................................................................