Two-phaseflowsinporousmedia:PredictionofpressuredropsusingadiffuseinterfacemathematicaldescriptionOriginalResearchArticle

Intheframeworkofitsresearchprogrammeonseverenuclearreactoraccidents,theInstitutdeRadioprotectionetdeSûretéNucléaire(IRSN)investigatesthewaterfloodingofanoverheatedporousbed,wherecomplextwo-phaseflowsarelikelytoexist.Abetterunderstandingoftheflowattheporelevelappearstobenecessaryinordertojustifyandimproveclosurelawsofmacroscopicmodels.Toinvestigatethelocalfeaturesofatwo-phaseflowincomplexgeometries,twoalternativewaysareavailable:experimentswithhighaccuracylocalmeasurementsordirectnumericalsimulation(DNS)oftheflowsinsmall-scalevolumes.Withintheframeworkofthesecondgradienttheory,diffuseinterfacemodelscanbederivedforbothsingle-componentandbinaryfluids.ThelattermodelisoftenreferredtoastheCahn–Hilliardmodel.Inthispaper,theCahn–Hilliardmodelisusedtosimulateimmiscibletwo-phaseflowsinarepresentativegeometryofaparticlebed.Theresultsareusedtocharacterizetheconfigurationofthephasesandpossibleflowregimesasafunctionofthesaturation.Correlationsfortherelativepermeabilitiesofeachphaseasafunctionofsaturationarealsopresented.Theresultsarediscussedandcomparedwithclassicalcorrelations.