computional modeling of gas-solid and gas-liquid f

ClarksonUniversityCOMPUTATIONALMODELLINGOFGAS-SOLIDANDGAS-LIQUIDFLOWSAPh.D.DissertationbyHojjatNasrDepartmentofMechanicalandAeronauticalEngineeringSubmittedinPartialFulfillmentoftheRequirementsFortheDegreeofDoctorofPhilosophy(MechanicalEngineering)May2009AcceptedbytheGraduateSchool__________________________________________DateDeanUMINumber:3376481INFORMATIONTOUSERSThequalityofthisreproductionisdependentuponthequalityofthecopysubmitted.Brokenorindistinctprint,coloredorpoorqualityillustrationsandphotographs,printbleed-through,substandardmargins,andimproperalignmentcanadverselyaffectreproduction.Intheunlikelyeventthattheauthordidnotsendacompletemanuscriptandtherearemissingpages,thesewillbenoted.Also,ifunauthorizedcopyrightmaterialhadtoberemoved,anotewillindicatethedeletion.______________________________________________________________UMIMicroform3376481Copyright2009byProQuestLLCAllrightsreserved.ThismicroformeditionisprotectedagainstunauthorizedcopyingunderTitle17,UnitedStatesCode._______________________________________________________________ProQuestLLC789EastEisenhowerParkwayP.O.Box1346AnnArbor,MI48106-1346iiTheundersignedhaveexaminedthedissertationentitledCOMPUTATIONALMODELLINGOFGAS-SOLIDANDGAS-LIQUIDFLOWSpresentedbyHojjatNasr,acandidateforthedegreeofDoctorofPhilosophy,andherebycertifythatitisworthyofacceptance.________________________________________________________DateADVISORGoodarzAhmadiEXAMININGCOMMITTEE_______________________________Dr.JohnB.McLaughlin________________________________Dr.DanielValentine________________________________Dr.SureshDhaniyala_________________________________Dr.PierMarzoccaiiiAbstractThisdissertationisconcernedwithcomputationalsimulationsofgas-solidandgas-liquidflows.Forthegas-solidstudies,theinteractionofsphericalsolidparticleswithturbulenceinafullydevelopedturbulentchannelflowwasstudied.TheEulerianframeworkwasusedforthegas-phase,whereastheparticle-phasewastreatedviaaLagrangianpointofview.Thetime-dependentthree-dimensionalNavier-Stokesequationswerenumericallysolvedusingdirectnumericalsimulation(DNS)viaapseudospectraltechnique.TheLagrangianparticleequationofmotionincludedthewall-correctednonlineardragforce,andthewall-inducedandshear-inducedliftforce.Tohaveabetterunderstandingofthemechanismsgoverningtheinteractionofparticleswiththeirsurroundings,one-way,two-wayandfour-waycouplingapproachesweretakenintoconsideration.Theinfluenceofparticlesontheflowwasmodeledbydistributingtheparticlefeedbackforceonthecomputationalgridpoints.Thehardsphereparticle-particlecollisionmodelbasedontheassumptionofbinarycollisionswasimplementedintheanalysis.Inthecaseofone-waycoupling,thenumericalpredictionswerecomparedwiththeexistingsimulationresultsandfavorableagreementwasachieved.Severalsimulationsfordifferentparticlerelaxationtimesandparticlemassloadingswereperformed.Forthesizerangesconsidered,thenumericalpredictionsshowedthattheadditionofparticlesattenuatestheintensityoffluidturbulencefluctuationsandasparticlemassloadingincreases,thelevelofattenuationincreases.Itwasshownthatinter-particlecollisionsincreasedtheparticledepositionvelocityasparticlemassloadingincreased,whiletwowaycouplingdecreasedtheparticledepositionrate.Inthephysicalcase(fourwaycoupling),theparticledepositionvelocityincreasedcomparedwiththeonewaycouplingcase.Forhighinertialparticles(70mPcopperparticles),inter-particlecollisionsdominatedthebehaviorofparticles,whiletwo-waycouplinghadnosignificanteffectsonparticlephasicfluctuations.Forthestudiesofgas-liquidflows,theunsteadylaminarNavier-SokesequationwassolvedineachphaseusingafixedEuleriangrid,andtheVolumeofFluid(VOF)techniquewasusedtoaccountfortrackingthegas/liquidinterface.Asabenchmark,atwo-dimensionalcomputationalmodelofamovingridgeonasurfaceduetoawettabilitygradientwasstudied,andthevelocityoftheridgealongthesurfacewascomparedwiththeanalyticalexpressionofBrochard(1989).ivSeveralcomputersimulationsforthemotionofliquiddropsthrough2Dand3Dfabricsunderdifferentconditionssuchasthedistancebetweenfibers,contactangledistribution,anddropinitialvelocitywereperformedtoidentifythekeyissuesforpenetratingaliquiddropthroughafabric.vAcknowledgementIwouldliketothankmyadvisorDr.GoodarzAhmadiforhisinvaluableguidance,encouragementandpatienceduringthecourseofmyPh.D.study.IwouldalsoliketothankDr.JohnB.McLaughlinforhisadviceandhelpfulcriticismontheresearchtopics.Iwouldliketothankmyexaminingcommittee:Dr.DanielValentine,Dr.SureshDhaniyala,andDr.PierMarzoccafortheinterestandhelp.viContents1.Introduction…………………………..…………………………………………............……..11.1Gas-solidflows………………………..………………………............…………………..11.1.1One-waycoupling…………………………………............………………………...11.1.2Two-waycoupling………………………………............…………………………..21.1.3Four-waycoupling……………………………............……………………………..31.2Gas-liquidflows…………………………………………............………………………..41.3Objectives………………………………………………………............…………………51.3.1Gas-solidflows…………………………..…………………............…………...…..51.3.2Gas-liquidflows………………………..……………...………............………...…..61.4Scope…