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【英文标准名称】:StandardTestMethodforCalculationofStagnationEnthalpyfromHeatTransferTheoryandExperimentalMeasurementsofStagnation-PointHeatTransferandPressure
【原文标准名称】:通过临界点传热与压力的热传递理论和实验测量来计算临界热函的标准试验方法
【标准号】:ASTME637-2005
【标准状态】:现行
【国别】:
【发布日期】:2005
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:E21.08
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:航空航天运输;焓;热传递;材料;数学计算;测量;压力;航天技术;临界点
【英文主题词】:enthalpydistribution;enthalpyprofile;localenthalpy;stagnationenthalpy
【摘要】:Thepurposeofthistestmethodistoprovideastandardcalculationofthestagnationenthalpyofanaerodynamicsimulationdeviceusingtheheattransfertheoryandmeasuredvaluesofstagnationpointheattransferandpressure.Astagnationenthalpyobtainedbythistestmethodgivesaconsistentsetofdata,alongwithheattransferandstagnationpressureforablationcomputations.1.1Thistestmethodcoversthecalculationfromheattransfertheoryofthestagnationenthalpyfromexperimentalmeasurementsofthestagnation-pointheattransferandstagnationpressure.1.2Advantages1.2.1Avalueofstagnationenthalpycanbeobtainedatthelocationinthestreamwherethemodelistested.Thisvaluegivesaconsistentsetofdata,alongwithheattransferandstagnationpressure,forablationcomputations.1.2.2Thiscomputationofstagnationenthalpydoesnotrequirethemeasurementofanyarcheaterparameters.1.3LimitationsandConsiderationsTherearemanyfactorsthatmaycontributetoanerrorusingthistypeofapproachtocalculatestagnationenthalpy,including:1.3.1TurbulenceTheturbulencegeneratedbyaddingenergytothestreammaycausedeviationfromthelaminarequilibriumheattransfertheory.1.3.2Equilibrium,Nonequilibrium,orFrozenStateofGasThereactionratesandexpansionsmaybesuchthatthegasisfarfromthermodynamicequilibrium.1.3.3NoncatalyticEffectsThesurfacerecombinationratesandthecharacteristicsofthemetalliccalorimetermaygiveaheattransferdeviationfromtheequilibriumtheory.1.3.4FreeElectricCurrentsThearc-heatedgasstreammayhavefreeelectriccurrentsthatwillcontributetomeasuredexperimentalheattransferrates.1.3.5NonuniformPressureProfileAnonuniformpressureprofileintheregionofthestreamatthepointoftheheattransfermeasurementcoulddistortthestagnationpointvelocitygradient.1.3.6MachNumberEffectsThenondimensionalstagnation-pointvelocitygradientisafunctionoftheMachnumber.Inaddition,theMachnumberisafunctionofenthalpyandpressuresuchthataniterativeprocessisnecessary.1.3.7ModelShapeThenondimensionalstagnation-pointvelocitygradientisafunctionofmodelshape.1.3.8RadiationEffectsThehotgasstreammaycontributearadiativecomponenttotheheattransferrate.1.3.9HeatTransferRateMeasurementAnerrormaybemadeintheheattransfermeasurement(seeMethodE469andTestMethodsE422,E457,E459,andE511).1.3.10ContaminationTheelectrodematerialmaybeofalargeenoughpercentageofthemassflowratetocontributetotheheattransferratemeasurement.1.4ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:A54
【国际标准分类号】:
【页数】:16P.;A4
【正文语种】: