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1、ChemicalEngineeringScience56(2001)673}681Simulationofaslurryairliftusingatwo-#uidmodelR.S.Oey*,R.F.Mudde,L.M.Portela,H.E.A.vandenAkkerKramersLaboratoriumvoorFysischeTechnologie,DelftUniversityofTechnology,PrinsBernhardlaan6,2628BWDelft,NetherlandsAbstractAt
2、wo-#uidapproachisusedtosimulatethe#owofathree-phasemixtureinaninternal-loopairliftreactor.Theloopconsistsofariser,inwhichgasisinjectedandtwodowncomersonbothsides.Theairliftloopisat"rsttreatedasatwo-phasesystem(gas}liquid).Afulltwo-#uidformulationisusedtodes
3、cribethedynamicsofthetwo-phase#ow.Subsequently,thedistributionofthethird,solidphaseisconsideredbysolvingamassbalanceinwhichthesolidsvelocityisthesuperpositionoftheliquidvelocity,agravitationalsettlingandturbulentdispersion.AnextendedversionofTchen'stheoryis
4、appliedforthedispersedphases;turbulenceinthecarrier-phaseismodelledbyamodi"edk}eequation.Themodelisimplementedinthein-house"nite-volumecodeDISSIM(Lathouwers,D.(1999).Modellingandsimulationofturbulentbubbly#ow.Ph.D.Thesis),a2-Dpressure-basedcode.Variationoft
5、hegas#owraterevealedtheexistenceofdi!erent#owregimewithrespecttothegasfractioninthedowncomer,inagreementwithliterature.Incasethegasseparationatthetopiscomplete,thecirculationvelocitysimulatedagreedwellwithasimplemechanicalenergybalance.Thesolidphaseisfoundt
6、oaccumulateinthedeadcornersiftheturbulentdispersionisignored.Thesettlingprocessisveryslowandpartofthesolidsaretrappedinthecirculationoftheliquid.Whentheturbulentdispersionistakenintoaccountasmoothsolidsdistributionisfoundwithahighervolumefractionofsolidsint
7、helowerpartofthedowncomers,wheretheliquidvelocityisminimal.(2001ElsevierScienceLtd.Allrightsreserved.Keywords:Internal-loopairliftreactor;CFD;Two-#uidmodel;Turbulence;k}emodel;Three-phase#ow1.IntroductionmethodsforCFDaretheEulerian}Eulerian(Sokolichin&Eigen
8、berger,1999)andtheEulerian}LagrangianInternal-loopairliftreactorsarewidelyusedinbio-approach(e.g.Lainetal.,1999)bothwiththeiradvant-technologyandchemicalindustry.Theyaresuitableforagesanddisadvantagesa
