ASTM C518-2010 使用热流计测定稳态热传导特性的标准试验方法

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【英文标准名称】:StandardTestMethodforSteady-StateThermalTransmissionPropertiesbyMeansoftheHeatFlowMeterApparatus
【原文标准名称】:使用热流计测定稳态热传导特性的标准试验方法
【标准号】:ASTMC518-2010
【标准状态】:现行
【国别】:美国
【发布日期】:2010
【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】:C16.30
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:calibration;erroranalysis;heatflowmeterapparatus;thermalresistance;heatflux;instrumentverification;thermalconductivity;thermaltesting
【摘要】:Thistestmethodprovidesarapidmeansofdeterminingthesteady-statethermaltransmissionpropertiesofthermalinsulationsandothermaterialswithahighlevelofaccuracywhentheapparatushasbeencalibratedappropriately.Propercalibrationoftheheatflowmeterapparatusrequiresthatitbecalibratedusingspecimen(s)havingthermaltransmissionpropertiesdeterminedpreviouslybyTestMethodsC177,orC1114.Note18212;Calibrationoftheapparatustypicallyrequiresspecimensthataresimilartothetypesofmaterials,thermalconductances,thicknesses,meantemperatures,andtemperaturegradientsasexpectedforthetestspecimens.Thethermaltransmissionpropertiesofspecimensofagivenmaterialorproductmayvaryduetovariabilityofthecompositionofthematerial;beaffectedbymoistureorotherconditions;changewithtime;changewithmeantemperatureandtemperaturedifference;anddependuponthepriorthermalhistory.Itmustberecognized,therefore,thattheselectionoftypicalvaluesofthermaltransmissionpropertiesrepresentativeofamaterialinaparticularapplicationshouldbebasedonaconsiderationofthesefactorsandwillnotapplynecessarilywithoutmodificationtoallserviceconditions.Asanexample,thistestmethodprovidesthatthethermalpropertiesshallbeobtainedonspecimensthatdonotcontainanyfreemoisturealthoughinservicesuchconditionsmaynotberealized.Evenmorebasicisthedependenceofthethermalpropertiesonvariables,suchasmeantemperatureandtemperaturedifference.Thesedependenciesshouldbemeasuredorthetestmadeatconditionstypicalofuse.Specialcareshallbetakeninthemeasurementprocedureforspecimensexhibitingappreciableinhomogeneities,anisotropies,rigidity,orespeciallyhighorlowresistancetoheatflow(seePracticeC1045).Theuseofaheatflowmeterapparatuswhentherearethermalbridgespresentinthespecimenmayyieldveryunreliableresults.Ifthethermalbridgeispresentandparalleltotheheatflowtheresultsobtainedmaywellhavenomeaning.Specialconsiderationsalsoarenecessarywhenthemeasurementsareconductedateitherhighorlowtemperatures,inambientpressuresaboveorbelowatmosphericpressure,orinspecialambientgasesthatareinertorhazardous.Thedeterminationoftheaccuracyofthemethodforanygiventestisafunctionoftheapparatusdesign,oftherelatedinstrumentation,andofthetypeofspecimensundertest(seeSection11),butthistestmethodiscapableofdeterminingthermaltransmissionpropertieswithinx00B1;2%ofthosedeterminedbyTestMethodC177whentheambienttemperatureisnearthemeantemperatureofthetest(T(ambient)=T(mean)x00B1;1x00B0;C),andintherangeof10to40x00B0;C.Inallcasestheaccuracyoftheheatflowmeterapparatuscanneverbebetterthantheaccuracyoftheprimarystandardsusedtocalibratetheapparatus.Whenthistestmethodistobeusedforcertificationtestingofproducts,theapparatusshallhavethecapabilitiesrequiredinA1.7andoneofthefollowingproceduresshallbefollowed:Theapparatusshallhaveitscalibrationcheckedwithin24hbeforeorafteracertificationtestusingeithersecondarytransferstandardstraceableto,or...........
【中国标准分类号】:A54
【国际标准分类号】:91_120_10
【页数】:15P.;A4
【正文语种】:英语