Theoreticalmodelingofcondensationofsteamoutsidedifferentverticalgeometries(tube,flatplates)inthepresenceofnoncondensablegaseslikeairandheliumOriginalResearchArticle

Condensationofsteamcomingoutfromthecoolantpipeduringalossofcoolantaccident(LOCA)playsakeyroleinremovingheatfromtheprimarycontainmentoftheadvancednuclearreactor(ANR).Thepresenceoflargemassfractionsofair(Wair=0.25–0.9)andasmallmassfractionofhelium(WHe=0.017–0.083)reducestheoverallheattransfercoefficient(HTC)substantially.Thepresentworkemphasizesontheissuethatmodelingthediffusionofwater-vaporthroughthegas–liquidinterfaceisthekeytogivegoodpredictionsinHTC.Inthis,condensationconductivityandeffectivediffusivityplaysakeyrole.Therefore,modificationshavebeenmadeinthederivationforcalculationofcondensationconductivityinthecaseofsteam–airmixtureandeffectivediffusivity(inthecaseofmulticomponentmixture).ThemodelvalidationhasbeendonewiththeexperimentaldataofDehbietal.[Dehbi,A.A.,Golay,M.W.,Kazimi,M.S.,1991.NationalConferenceofHeatTransferAIChESymposiumSeries,pp.19–28]andAndersonetal.[Anderson,M.H.,Herranz,L.E.,Corradini,M.L.,1998.ExperimentalanalysisofheattransferwithintheAP600containmentunderpostulatedaccidentconditions.Nucl.Eng.Des.185,153–172]andotheranalyticalmodelsavailableintheliterature[Herranz,L.E.,Anderson,M.H.,Corradini,M.H.,1998a.Theeffectoflightgasesinnoncondensablemixturesoncondensationheattransfer.Nucl.Eng.Des.183,133–150;Herranz,L.E.,Anderson,M.H.,Corradini,M.L.,1998b.AdiffusionlayermodelforsteamcondensationwithintheAP600containment.Nucl.Eng.Des.185,153–172;Peterson,P.F.,Schrock,Y.E.,Kageyama,T.,1993.Diffusionlayertheoryforturbulentvaporcondensationwithnoncondensablegases.J.HeatTransf.,115;Dehbi,A.A.,Golay,M.W.,Kazimi,M.S.,1991.NationalConferenceofHeatTransferAIChESymposiumSeries,pp.19–28].Sincethevalidationsoftheresultswerefoundsatisfactory,thedatasets[Dehbi,A.A.,Golay,M.W.,Kazimi,M.S.,1991.NationalConferenceofHeatTransferAIChESymposiumSeries,pp.19–28;Anderson,M.H.,Herranz,L.E.,Corradini,M.L.,1998.ExperimentalanalysisofheattransferwithintheAP600containmentunderpostulatedaccidentconditions.Nucl.Eng.Des.185,153–172]havebeencomparedwithawiderangeofsubcoolingandtheoperatingpressures.Anextensivecomparisonhasbeenreportedandtheresultspredictedbythepresentmodelwerefoundtobesatisfactory.