产品的热设计(Thermal introduction)

IntroductionofThermalGGT/RE–EnvironmentTestTeamPrimaryMechanicofHeatTransferThermalenergytransport:causebytemperaturedifference,highT-lowTConductionHeattransferringbysolidmediumConvectionTransferringenergybetweensolidsurfaceandfluidMasstransportNatural(free)convectionForcedconvectionRadiationHeattransferringbyelectromagneticwavesConductionFourier’sLawQ=-KAΔT/ΔLQ:heattransferrateA:cross-sectionalareaofheatfluxΔT/ΔL:temperaturegradientK:thermalconductivity(W/mk)Ex.Al=230Cu=380Mylar=1.8ConvectionNewtoniancoolingLawQc=hcAs(Ts–Ta)Qc:convectionheattransferrateAs:surfaceareaTs:surfacetemperatureofsolidTa:tmperatureofambienthc:heattransfercoefficient,f(flowtype,bodygeometry,physicalproperty,temperature,velocity,viscosity…)Naturalconvection&Forcedconvctionhcofair,naturalconvection:0.0015~0.015W/in2℃forcedconvection:0.015~0.15W/in2℃RadiationQa=εσAF1-2(Ts4–Ta4)Qa:radiationheattransferrateε:emissivity,0≦ε≦1σ:Stefan-BoltzmannconstantA:surfaceareaF1-2:viewfactorTs:temperatureofbodysTa:temperatureofbodyaThermalResistanceR=V/IV:voltage=ΔT:temperaturedifferenceI:current=Q:heatConductionRk=ΔL/KAkConvectionRs=1/hcAsRadiationRa=(Ts–Ta)/εσAF1-2(Ts4–Ta4)BasicConceptsforNBThermalDesignThermalDesignTargetThermaldesignmustmeetthermalspec.ofCPU,allkeycomponents(HDD,FDD,CD-ROM,PCMCIA…),andallICchips(Chipset,VGA,RAM,PCMCIA…),andallICchips(Chipset,VGA,RAM,Audio…)ineachuserconditionsThermalResistanceΘj-a=(Tj–Ta)/PcpuΘj-a:CPUjunctiontoambientthermalresistanceTj:CPUjunctiontemperatureTa:ambienttemperaturePcpu:CPUpowerBasicConceptsforNBThermalDesignSystemThermalCouplingeffectΘj-a=(Tj–Ta–Tsys)/PcpuTsys:systemtemperature=Psys*Θ=ΣPi*θi,(i:DRAM,Chipset,HDD,FDD,CD-ROM…)R:thermalcouplingfactorbetweenPcpuandPsysTj:CPUspec.forIntel:100℃Ta:OEMspec.,35℃Θj-a,Tsys:OEMdesigndependent,Tsys=10~15℃BasicConceptsforNBThermalDesignThermalSolutionsPassivethermalsolutionActivethermalsolutionHybridthermalsolutionRHERemoteHeatExchangerBasicConceptsforNBThermalDesignCharacteristicofagoodpassivecomponentsSpreaderplateconnectedtoCPUshouldbeaslargeaspossibleTemperaturevariationonspreaderplateshouldbeminimalCharacteristicofagoodactivecomponentAirinletandoutletshouldbeclearlydefinedLengthofairpassagethroughNBshouldbesmalltokeeppressuredroplow,flowratehighPossiblereducenoiselevelofthefanDesignmustbecapableofventingaportionofhotairfromNBinsideImportantComponentsForThermalDesignHeatSinkHeatPipeFanTIM(ThermalInterfaceMaterial)CombinationofaforementionedcomponentsHeatSinkMaterialMaterial:A1050A6063ADC12C1100K(W/mk):230210192384Specificgravity:2.712.692.708.92ProductionDie-castingExtrudedQ=-KAΔT/ΔLFin,Q=hAΔTDie-casting,extrusion,folder,stack,solderingfinsHeatPipeBasicconfigurationandcharacteristicBasicspecificationMaterial:copperWorkingfluid:purewaterStandardworkingtemperature:0~100℃Size:ψ3,ψ4,ψ5,ψ6,ψ8TypicalheatpipewickstructuresFiber,mesh,groove,powderTypicalmodificationofheatpipeFlatteningBendingHeatPlateFanStructureRotator:magneticblade,shaftStator:bearing,wire,stainlessplateControlcircuitTheoryTypeAxialfanBlowerfanSelectionTotalcoolingrequirementQ=Cp*m*ΔT=ρ*Cp*CFM*ΔTTotalsystemresistance/systemcharacteristiccurveSystemoperatingpointFanParallelandseriesoperationAcousticalnoiselevel(dB)ToachievelownoiseshouldconsiderSystemimpedanceFlowdisturbanceFanspeedandsizeTemperatureriseVibrationVoltagevariationDesignconsiderationsTIMThermalInterfaceMaterialToreducecontactthermalresistancebetweenCPUdieandthermalmoduleImportantofTIMMaterialVariousmaterial:silicon-base,carbon…Non-phasechangePhasechangePressureeffectPressurespec.onCPUspec.100psiThermalDesignProcedureClarifyThermalSpecificationDesignThermalSolutionAnalyticApproachEvaluateSolutionPerformanceNumericalApproachExperimentApproachVerifyDesignThermalSolutionEvaluateheatgenerationAllowablethermalresistanceAllowabledesignspaceEvaluateChassisheatdissipationEvaluateheatexchangeareaEvaluatefanflowratePassFailInspectStructure.Productionmethod.Cost…RecommendThermalSolutionThermalTestinWorkingSampleVerifyOverallSystemMeetingThermalSpecificationThermalDesignOK!ExamineandModifyThermalSolutionPassFailThermalDesignGuidesDesignguideforthermal(Ver.0.2)ThankYou!fiberMesh細絲(銅絲)螺旋彈片銅网groove直接加工而成Powder類型:金屬粉末燒結在HeatPipe內壁,形成毛細結構NNNNSSSS無刷馬達轉動原理有HallIC感應其磁鐵N.S.極,經由電路控制其線圈之導通產生內部激磁使轉子部旋轉CFM(ft3/min)StaticpressureSystemresistancecurveFancurveSystemoperatingpoint1.ThermalModule1)Reservespaceforthermalmodule(Intelrecommendation)Coppermine:70*50*11.5mmTualatin:75*55*11.5mmNorthwood:85*60*19mm2)Itshouldreserveagapbetweenthermalmoduleandtopcover(keyboardcover)1.ThermalModule3)ThegapbetweenthermalmoduleexitandNBcaseventshouldbesealedwellsothehotaircouldn’tflowbacktosystem.Ifleaveanopengapalongairflowpath,itwillaffectthermalefficiencyandacousticnoise.1.ThermalModule4)ThethermalmoduleandCPUshouldcontactwell.a)ThemaxpressureofthethermalmoduleonCPUis100psi.WithinSPEC,efficiencyofthermalmoduleincreaseswithpressure.b)It’sbettertofixmoduleonM/Bbyfourscrews(avoidingthreescrews)andspringdesign.2.Fan1)Faninletconstraints:gap3~5mmis