Fluid-to-fluidmodelingofcriticalheatfluxin4×4rodbundlesOriginalResearchArticle

Fluid-to-fluidmodelingofcriticalheatflux(CHF)istosimulatetheCHFbehaviorsforwaterbyemployinglowcostmodelingfluid,andtheflowscalingfactoristhekeytoapplythetechniquetofuelbundles.TheCHFexperimentsin4×4rodbundleshavebeencarriedoutinFreon-12loopinequivalentnuclearreactorwaterconditions(P=10.0–16.0MPa,G=488.0–2100.0kg/m2s,Xcr=−0.20–0.30).Themodelsinfluid-to-fluidmodelingofCHFisverifiedbytheCHFdataforFreon-12obtainedintheexperimentandtheCHFcorrelationforwaterobtainedbyNuclearPowerInstituteofChina(NPIC)inthesame4×4rodbundles.IthasbeenfoundthattheS.Y.AhmadCompensationDistortionmodel,theLuZhongqimodel,theGroeneveldmodelandStevens–KirbymodeloverpredictthebundlesCHFvaluesforwater.Thenanempiricalcorrelationofflowscalingfactorisproposed.ComparisonoftheCHFdataintwokindsoftestsectionsforFreon-12,inwhichthedistanceofthelastgridawaytheendofheatedlengthisdifferent,showsthatthespacergrid,whichislocatedat20mmawayfromtheendoftheheatedlength,hasevidentlyinfluencedontheCHFvalueinthe4×4rodbundlesforFreon-12.Thisisdifferentfromthatforwater,andtheneedforfurtherworkisrequired.