【英文标准名称】:StandardTestMethodforMeasuringHeatFluxUsingFlush-MountedInsertTemperature-GradientGages
【原文标准名称】:使用嵌装温度梯度表测量热通量的标准试验方法
【标准号】:ASTME2683-2009
【标准状态】:现行
【国别】:
【发布日期】:2009
【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】:
【英文主题词】:heat-fluxgage;temperaturegradient;thermaltransport
【摘要】:Thepurposeofthistestmethodistomeasurethenetheatfluxtoorfromasurfacelocation.Formeasurementoftheradiantenergycomponenttheemissivityorabsorptivityofthesurfacecoatingofthegageisrequired.Whenmeasuringtheconvectiveenergycomponentthepotentialphysicalandthermaldisruptionsofthesurfacemustbeminimizedandcharacterized.Requisiteistoconsiderhowthepresenceofthegagealtersthesurfaceheatflux.Thedesiredquantityisusuallytheheatfluxatthesurfacelocationwithoutthepresenceofthegage.Temperaturelimitationsaredeterminedbythegagematerialproperties,themethodofmountingthesensingelement,andhowtheleadwiresareattached.Therangeofheatfluxthatcanbemeasuredandthetimeresponsearelimitedbythegagedesignandconstructiondetails.Measurementsofafractionof1kW/m2toabove10MW/m2areeasilyobtainedwithcurrentgages.Withthinfilmsensorsatimeresponseoflessthan10x03BC;sispossible,whilethickersensorsmayhaveresponsetimesontheorderof1s.Itisimportanttochoosethegagestyleandcharacteristicstomatchtherangeandtimeresponseoftherequiredapplication.Whendifferentialthermocouplesensorsareoperatedasspecifiedforone-dimensionalheatfluxandwithinthecorrespondingtimeresponselimitations,thevoltageoutputisdirectlyproportionaltotheheatflux.Thesensitivity,however,maybeafunctionofthegagetemperature.Themeasuredheatfluxisbasedonone-dimensionalanalysiswithauniformheatfluxoverthesurfaceofthegage.Measurementsofconvectiveheatfluxareparticularlysensitivetodisturbancesofthetemperatureofthesurface.Becausetheheat-transfercoefficientisalsoaffectedbyanynon-uniformitiesinthesurfacetemperature,theeffectofasmalltemperaturechangewithlocationisfurtheramplifiedasexplainedbyMoffatetal.(2)andDiller(3).Moreover,thesmallerthegagesurfacearea,thelargeristheeffectontheheattransfercoefficientofanysurfacetemperaturenon-uniformity.Therefore,surfacetemperaturedisruptionscausedbythegageshouldbekeptmuchsmallerthanthesurfacetoenvironmenttemperaturedifferencedrivingtheheatflux.Thisnecessitatesagoodthermalpathbetweenthesensorandthesurfaceintowhichitismounted.Ifthegageisnotwatercooled,agoodthermalpathwaytothesystemx2019;sheatsinkisimportant.Thegageshouldhaveaneffectivethermalconductivityasgreatorgreaterthanthesurroundingmaterial.Itshouldalsohavegoodphysicalcontactinsuredbyatightfitintheholeandamethodtotightenthegageintothesurface.AnexamplemethodusedtotightenthegagetothesurfacematerialisillustratedinFig.2.Thegagehousinghasaflangeandaseparatetighteningnuttappedintothesurfacematerial.Ifthegageiswatercooled,thethermalpathwaytotheplateislessimportant.Theheattransfertothegageentersthewaterastheheatsinkinsteadofthesurroundingplate.Consequently,thethermalresistancebetweenthegageandplatemayevenbeincreasedtodiscourageheattransferfromtheplatetothecoolingwater.Unfortunately,thismayalsoincreasethethermalmismatchbetweenthegageandsurroundingsurface.Fig.2showsaheatfluxgagemountedintoaplatewiththesurfacetemperatureofthegageofTsandthesurfacetemperatureofthesurroundingplateofTp.Aspreviouslydiscussed,adifferenceintemperaturebetweenthegageandplatemayalsoincreasethelocalheattransfercoefficientoverthegage.Thisamplifiesthemeasurementerror.Consequently,awelldesignedheatfluxgagewillkeepthetemperaturedifference........
【中国标准分类号】:
【国际标准分类号】:17_200_10
【页数】:7P.;A4
【正文语种】: