【英文标准名称】:StandardPracticeforEstimateoftheHeatGainorLossandtheSurfaceTemperaturesofInsulatedFlat,Cylindrical,andSphericalSystemsbyUseofComputerPrograms
【原文标准名称】:用计算机程序估测绝热的平面系统、圆柱形和球形系统的表面温度及吸热或热损失的标准实施规范
【标准号】:ASTMC680-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【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】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:computerprogram;heatflow;heatgain;heatloss;pipe;thermalinsulation;Algorithms;Computerprograms;Cylindricalthermalinsulation;Flatthermalinsulation;Heatingtests--thermalinsulation;Insulatedflatsurfaces/pipes;Insulatedpipe/equi
【摘要】:Manufacturersofthermalinsulationexpresstheperformanceoftheirproductsinchartsandtablesshowingheatgainorlossperunitsurfaceareaorunitlengthofpipe.Thisdataispresentedfortypicalinsulationthicknesses,operatingtemperatures,surfaceorientations(facingup,down,horizontal,vertical),andinthecaseofpipes,differentpipesizes.Theexteriorsurfacetemperatureoftheinsulationisoftenshowntoprovideinformationonpersonnelprotectionorsurfacecondensation.However,additionalinformationoneffectsofwindvelocity,jacketemittance,ambientconditionsandotherinfluentialparametersmayalsoberequiredtoproperlyselectaninsulationsystem.Duetothelargenumberofcombinationsofsize,temperature,humidity,thickness,jacketproperties,surfaceemittance,orientation,andambientconditions,itisnotpracticaltopublishdataforeachpossiblecase,Refs(31,32).Usersofthermalinsulationfacedwiththeproblemofdesigninglargethermalinsulationsystemsencountersubstantialengineeringcosttoobtaintherequiredinformation.Thiscostcanbesubstantiallyreducedbytheuseofaccurateengineeringdatatables,oravailablecomputeranalysistools,orboth.Theuseofthispracticebybothmanufacturersandusersofthermalinsulationwillprovidestandardizedengineeringdataofsufficientaccuracyforpredictingthermalinsulationsystemperformance.However,itisimportanttonotethattheaccuracyofresultsisextremelydependentontheaccuracyoftheinputdata.Certainapplicationsmayneedspecificdatatoproducemeaningfulresults.Theuseofanalysisproceduresdescribedinthispracticecanalsoapplytodesignedorexistingsystems.Intherectangularcoordinatesystem,PracticeC680canbeappliedtoheatflowsnormaltoflat,horizontalorverticalsurfacesforalltypesofenclosures,suchasboilers,furnaces,refrigeratedchambersandbuildingenvelopes.Inthecylindricalcoordinatesystem,PracticeC680canbeappliedtoradialheatflowsforalltypesofpipingcircuits.Inthesphericalcoordinatesystem,PracticeC680canbeappliedtoradialheatflowstoorfromstoredfluidssuchasliquefiednaturalgas(LNG).PracticeC680isreferencedforusewithGuideC1055andPracticeC1057forburnhazardevaluationforheatedsurfaces.Infraredinspection,in-situheatfluxmeasurements,orbothareoftenusedinconjunctionwithPracticeC680toevaluateinsulationsystemperformanceanddurabilityofoperatingsystems.Thistypeofanalysisisoftenmadepriortosystemupgradesorreplacements.Allporousandnon-poroussolidsofnaturalorman-madeoriginhavetemperaturedependentthermalconductivities.Thechangeinthermalconductivitywithtemperatureisdifferentfordifferentmaterials,andforoperationatarelativelysmalltemperaturedifference,anaveragethermalconductivitymaysuffice.Thermalinsulatingmaterials(kx003C;0.85{Btux00B7;in}/{hx00B7;ft2x00B7;x00B0;F})areporoussolidswheretheheattransfermodesincludeconductioninseriesandparallelflowthroughthematrixofsolidandgaseousportions,radiantheatexchangebetweenthesurfacesoftheporesorinterstices,aswellastransmissionthroughnon-opaquesurfaces,andtoalesserextent,convectionwithinandbetweenthegaseousportions.Withtheexistenceofradiationandconvectionmodesofheattransfer,themeasuredvalueshouldbecalledapparentthermalconductivityasdescribedinTerminologyC168.Themainreasonforthisisthatthepremiseforpureheatconductionisnolongervalid,becausetheot...........
【中国标准分类号】:Q25
【国际标准分类号】:27_220
【页数】:19P.;A4
【正文语种】:英语