Two-groupinterfacialareatransportinverticalair–waterflow:I.MechanisticmodelOriginalResearchArticle

Thepredictionofthedynamicalevolutionofinterfacialareaconcentrationisoneofthemostchallengingtasksintwo-fluidmodelapplication.Thispaperisfocusedondevelopingtheoreticalmodelsforinterfacialareasourceandsinktermsforatwo-groupinterfacialareatransportequation.Mechanisticmodelsofmajorfluidparticleinteractionphenomenainvolvingtwobubblegroupsareproposed,includingtheshearing-offofsmallbubblesfromslug/capbubbles,thewakeentrainmentofspherical/distortedbubblegroupintoslug/capbubblegroup,thewakeaccelerationandcoalescencebetweenslug/capbubbles,andthebreakupofslug/capbubblesduetoturbulenteddyimpacts.Theexistingone-groupinteractiontermsareextendedinconsideringthegenerationofcapbubbles,aswellasdifferentparametricdependenceswhenthesetermsareappliedtotheslugflowregime.Thecompletesetofmodelingequationsisclosedandcontinuouslycoversthebubblyflow,slugflow,andchurn-turbulentflowregimes.Predictionoftheinterfacialareaconcentrationevolutionusingaone-dimensionaltwo-grouptransportequationandevaluationwithexperimentalresultsaredescribedinacompanionpaper.