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1、IntroductionofThermalGGT/RE–EnvironmentTestTeamPrimaryMechanicofHeatTransferThermalenergytransport:causebytemperaturedifference,highT->lowTConductionHeattransferringbysolidmediumConvectionTransferringenergybetweensolidsurfaceandfluidMasstransportNatural(fre
2、e)convectionForcedconvectionRadiationHeattransferringbyelectromagneticwavesConductionFourier’sLawQ=-KAΔT/ΔLQ:heattransferrateA:cross-sectionalareaofheatfluxΔT/ΔL:temperaturegradientK:thermalconductivity(W/mk)Ex.Al=230Cu=380Mylar=1.8ConvectionNewtoniancoolin
3、gLawQc=hcAs(Ts–Ta)Qc:convectionheattransferrateAs:surfaceareaTs:surfacetemperatureofsolidTa:tmperatureofambienthc:heattransfercoefficient,f(flowtype,bodygeometry,physicalproperty,temperature,velocity,viscosity…)Naturalconvection&Forcedconvctionhcofair,natur
4、alconvection: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
5、:voltage=ΔT:temperaturedifferenceI:current=Q:heatConductionRk=ΔL/KAkConvectionRs=1/hcAsRadiationRa=(Ts–Ta)/εσAF1-2(Ts4–Ta4)BasicConceptsforNBThermalDesignThermalDesignTargetThermaldesignmustmeetthermalspec.ofCPU,allkeycomponents(HDD,FDD,CD-ROM,PCMCIA…),anda
6、llICchips(Chipset,VGA,RAM,PCMCIA…),andallICchips(Chipset,VGA,RAM,Audio…)ineachuserconditionsThermalResistanceΘj-a=(Tj–Ta)/PcpuΘj-a:CPUjunctiontoambientthermalresistanceTj:CPUjunctiontemperatureTa:ambienttemperaturePcpu:CPUpowerBasicConceptsforNBThermalDesig
7、nSystemThermalCouplingeffectΘj-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℃BasicConceptsforNB
8、ThermalDesignThermalSolutionsPassivethermalsolutionActivethermalsolutionHybridthermalsolutionRHERemoteHeatExchangerBasicConceptsforNBThermalDesignCharacteristicofagoodpassivecomponentsSpreaderplateconn