Abstract :
Acompleteanddetaileddescriptionofthetheoreticalbackgroundofan‘(1D)thermal-hydraulicdrift-fluxbasedmixture-fluid’coolantchannelmodelanditsresultingmoduleCCMwillbepresented.Theobjectiveofthismoduleistosimulateasuniversallyaspossiblethesteadystateandtransientbehaviourofthekeycharacteristicparametersofasingle-ortwo-phasefluidflowingwithinanytypeofheatedornon-heatedcoolantchannel.Duetothepossibilitythatdifferentflowregimescanappearalonganychannel,sucha‘basic(BC)’1Dchannelisassumedtobesubdividedintoanumberofcorrespondingsub-channels(SC-s).EachSCcanbelongtoonlytwotypesofflowregime,anSCwithjustasingle-phasefluid,containingexclusivelyeithersub-cooledwaterorsuperheatedsteam,oranSCwithatwo-phasemixtureflow.AfteranappropriatenodalisationofsuchaBC(andthereforealsoitsSC-s)a’modifiedfinitevolumemethod’hasbeenappliedforthespatialdiscretisationofthepartialdifferentialequations(PDE-s)whichrepresentthebasicconservationequationsofthermal-hydraulics.SpecialattentionhadtobegiventothepossibilityofvariableSCentranceoroutletpositions(whichdescribeboilingboundariesormixturelevels)andthusthefactthatanSCcanevendisappearorbecreatedanew.TheprocedureyieldsforeachSCtype(andthustheentireBC),asetofnon-linearordinary1storderdifferentialequations(ODE-s).
