ASTM C335/C335M-2010 管道隔热稳态热传导性能的标准试验方法

作者:标准资料网 时间:2024-05-15 04:41:52  浏览:8291   来源:标准资料网

【英文标准名称】:StandardTestMethodforSteady-StateHeatTransferPropertiesofPipeInsulation
【原文标准名称】:管道隔热稳态热传导性能的标准试验方法
【标准号】:ASTMC335/C335M-2010
【标准状态】:现行
【国别】:
【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】:表面导热系数;实验设计;辐射热传导;稳态热传导;热阻;管道热绝缘
【英文主题词】:apparentthermalconductivity;experimentaldesign;radialheattransfer;steadystateheattransfer;thermalresistance;Pipethermalinsulation
【摘要】:Asdeterminedbythistestmethod,thepipeinsulationlinealthermalresistanceorconductance(and,whenapplicable,thethermalresistivityorconductivity)aremeansofcomparinginsulationswhichincludetheeffectsoftheinsulationanditsfituponthepipe,circumferentialandlongitudinaljointing,andvariationsinconstruction,butdonotincludetheeffectsoftheoutersurfaceresistanceorheattransfercoefficient.Theyarethusappropriatewhentheinsulationouter-surfacetemperatureandthepipetemperatureareknownorspecified.However,sincethethermalpropertiesdeterminedbythistestmethodincludetheeffectsoffitandjointing,theyarenottruematerialproperties.Therefore,propertiesdeterminedbythistestmethodaresomewhatdifferentfromthoseobtainedonapparentlysimilarmaterialinflatformusingtheguardedhotplate,TestMethodC177,ortheheatflowmeterapparatus,TestMethodC518.Thepipeinsulationlinealthermaltransferenceincorporatesboththeeffectoftheinsulationanditsfituponthepipeandalsotheeffectofthesurfaceheat-transfercoefficient.Itisappropriatewhentheambientconditionsandthepipetemperatureareknownorspecifiedandthethermaleffectsofthesurfacearetobeincluded.Becauseofthetestconditionrequirementsprescribedinthistestmethod,recognizethatthethermaltransferpropertiesobtainedwillnotnecessarilybethevaluepertainingunderallserviceconditions.Asanexample,thistestmethodprovidesthatthethermalpropertiesshallbeobtainedbytestsondryorconditionedspecimens,whilesuchconditionsarenotnecessarilyrealizedinservice.Theresultsobtainedarestrictlyapplicableonlyfortheconditionsoftestandfortheproductconstructiontested,andmustnotbeappliedwithoutproperadjustmentwhenthematerialisusedatotherconditions,suchasmeantemperaturesthatdifferappreciablyfromthoseofthetest.Withthesequalificationsinmind,thefollowingapply:Forhorizontalorverticalpipesofthesamesizeandtemperature,operatinginthesameambientenvironment,valuesobtainedbythistestmethodcanbeusedforthedirectcomparisonofseveralspecimens,forcomparisontospecificationvalues,andforengineeringdataforestimatingheatlossofactualapplicationsofspecimensidenticaltothosetested(includinganyjacketsorsurfacetreatments).Whenappropriate,correctfortheeffectofendjointsandotherrecurringirregularities(4.4).Whenapplyingtheresultstoinsulationsizesdifferentfromthoseusedinthetest,anappropriatemathematicalanalysisisrequired.Forhomogeneousmaterials,thisconsistsoftheuseofthethermalconductivityorresistivityvalues(correctedforanychangesinmeantemperature)plustheuseofthesurfaceheattransfercoefficientwhentheambienttemperatureisconsidered(forexample,seePracticeC680).Fornonhomogeneousandreflectiveinsulationmaterials,amoredetailedmathematicalmodelisrequiredwhichproperlyaccountsfortheindividualmodesofheattransfer(conduction,convection,radiation)andthevariationofeachmodewithchangingpipesize,insulationthickness,andtemperature.Itisdifficulttomeasurethethermalperformanceofreflectiveinsulationthatincorporateaircavities,sincethegeometryandorientationoftheaircavitiescanaffectconvectiveheattransfer.Whileitisalwaysdesirabletotestfull-lengthpipesections,thisisnotalwayspossibleduetosizelimitationsofexistingpipeinsulationtesters.Ifinsulationsectionsaretestedlessthanfulllength,internalconvectiveheattransferare......
【中国标准分类号】:P94
【国际标准分类号】:91_100_60
【页数】:14P.;A4
【正文语种】: