Author/Authors :
ManfredBürger، نويسنده , , GeorgesBerthoud، نويسنده ,
Abstract :
AsalreadyindicatedbythecontributionsinPart1ofthisissue,anenhancedcoolabilitycanbeexpectedespeciallyfrommulti-dimensionalcoolantflowsinnon-uniformparticlebeds,comparedwithearlieranalysesbasedonone-dimensionalconfigurationsundertopfloodingandrelateddryoutheatfluxes(DHF).However,assuredbasiclocallawsoffrictionandheattransferinsuchbedsarerequiredtoreallyevaluatethecoolabilitypotentialwithmultidimensionalcomputercodes.Thus,asacommonsubject,thispartofthepresentissuereferstoexperimentalinvestigationsandrelatedmodellingonbasiclawsoffrictionandheattransferinparticlebeds.Sincesuchlawsareofteninvestigatedmainlywithrespecttodryoutphenomena(“dryoutheatflux”:DHF)thisconnectionisalsoaddressedhere.Ageneralimpressionisthattheapproachesarewidelyspread,asconcernsthespecificexperimentalaimsandmethods,therangeofconditionsanalysed,thephenomenaemphasised,theempiricallawsderivedandtheconclusionsindicatedforcoolability,especiallyunderreactorconditions.Thus,itappearstobeimportanttoconfronttheseapproacheswithoneanotherinordertofindacommonlineofmajorsubjectsandofderivationorvalidationofrelevantempiricallaws.Certainly,thiscannotbefinallyreachedhereandbythepresentissue.Afirststepisundertakenhere,tryingtodiscussremainingproblemsandtasksforfuturework.
