ANSYS CFX多相流教程

LagrangianParticleTracking-AdvancedFeaturesChapter8ANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseTrainingManualLagrangianParticleTracking-AdvancedFeaturesOctober10,2005Inventory#8-2•Otherparticleforces•Transientparticletracking•Particlebreakupmodels•Particlemasstransfer•ParticleerosionOverviewANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseTrainingManualLagrangianParticleTracking-AdvancedFeaturesOctober10,2005Inventory#8-3OtherForces•Electrostatic–Electricchargeofparticles–Precipitation,powderpainting•Magnetic–Metalseparation•Thermophoretic–Temperaturegradientsinplasmaflows–MHDgenerators•VanderWaalsadhesion–Adhesionbetweenparticlesandwalls–Nanoparticles•Near-wallliftanddrag–Non-homogeneousflow–Dragandliftincreaseatsmallwalldistancesy5dP•CanbedefinedinCFX-5viaUserdefinedforces(ParticleUserRoutine)ANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseTrainingManualLagrangianParticleTracking-AdvancedFeaturesOctober10,2005Inventory#8-4SteadyStatevs.Transient•SteadyStateParticles–Particlesarealwaystrackedfrom“birth”to“death”–Particlesmustnotberestarted–Allparticlesareinjectedatonce–One-waycoupledparticlesaresolvedattheendofthesimulation–Fullycoupledparticlesaresolvedatauserspecifiediterationinterval–Particletravelingtimeandparticletimearethesame•TransientParticles–Particlesaretrackedfrombeginningtoendofeachtimestep–Particlesmustberestarted–Atimestepstepspecificnumberofparticlesisinjected–One-waycoupledparticlesaresolvedattheendofeachtimestep–Fullycoupledparticlesaresolvedatauserspecifiedcoefficientloopintervalwithineachtimestep–Particletravelingtimeandparticletimearedifferent–Postprocessingoftime-integratedparticleinformationANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseTrainingManualLagrangianParticleTracking-AdvancedFeaturesOctober10,2005Inventory#8-5TransientParticles:ParticleIntegration•Integrationofparticlesoveractualtimestep:•PiecewiselinearforwardEulerintegration:FPFFtttt≤≤Δ−),(,,,tFtPttPfpφφφ=Δ+FtFFttΔ−FFttΔ−2TimeFtΔFtΔPtΔPtΔPtΔANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseTrainingManualLagrangianParticleTracking-AdvancedFeaturesOctober10,2005Inventory#8-6TransientParticles:ParticleIntegration•Time/spaceinterpolationofthefluidvariablestotheactualparticletimeandposition:•Timeinterpolationcanbecontrolledwithanexpertparameter:–pttimeinterpolation(Default:1)–0:usenewesttimeleveltF–1:linearinterpolation(usingtimelevelstFandtF-ΔtF)–2:quadraticinterpolation(usingtimelevelstF,tF-ΔtFandtF-2ΔtF)ÆrequiressecondordertransientschemeFtFFttΔ−FFttΔ−2TimeFtΔFtΔPtΔPtΔPtΔVertexttFttFtFtFFFf),,(2,,,,Δ−Δ−=φφφφANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseTrainingManualLagrangianParticleTracking-AdvancedFeaturesOctober10,2005Inventory#8-7TransientParticles:ParticleIntegration•Usedforcoefficientloopwithineachtimestep•Additionalcontrolsforfullycoupledparticles:–FirstIterationforParticleCalculation(1)–IterationFrequency(1)–ParticleSourceTarget(0.01)•Basedontherateofchangeofsources–UnderRelaxationFactors(1.0)•VelocityUnderRelaxationFactor•EnergyUnderRelaxationFactor•MassUnderRelaxationFactor•VelocityUnderRelaxationFactorforFirstParticleIntegration•EnergyUnderRelaxationFactorforFirstParticleIntegration•MassUnderRelaxationFactorforFirstParticleIntegration•VelocityUnderRelaxationFactoratTimeStepStart•EnergyUnderRelaxationFactoratTimeStepStart•MassUnderRelaxationFactoratTimeStepStartANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseTrainingManualLagrangianParticleTracking-AdvancedFeaturesOctober10,2005Inventory#8-8TransientParticleInjection•Transientparticlescanbeinjectedonboundarypatchesandparticleinjectionregions•SameCCLsyntaxasusedforsteady-stateparticles,except…•NumberofPositions:–DirectSpecificationsÆNumberperUnitTime,[s^-1]–ProportionaltoMassFlowRateÆNumberperUnitTimeandMassFlowRate,[kg^-1]ANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseTrainingManualLagrangianParticleTracking-AdvancedFeaturesOctober10,2005Inventory#8-9•Particlesareinjectedatstartoftimesteporaredistributedoverthetimestep•Logicalexpertparameter:–ptdistributetransparticles(Default=T)1.Timestep2.TimestepTimeParticlesaredistributedoverthetimestepParticlesareinjectedatstartofthetimestepTransientParticleInjectionANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseANSYSCFXMultiphaseTrainingManualLagrangianParticleTracking-AdvancedFeaturesOctober10,2005Inventory#8-10TransientParticleInjectionExample•Sprayinjection–Givenparticlemassflowdistribution:CEL:FUNCTION:MFPARTArgumentUnits=[s]Option=InterpolationResultUnits=[kgs^-1]INTERPOLATIONDATA:DataPairs=0,0.0,0.5,0,1,1,1.5,1,2,0,4,0ExtendMax=NoExtendMin=NoOption=OneDimensionalENDENDEXPRESSIONS:DT=0.05[s]MFPARTMAX=1[kgs^-1]NPART=100/DT/MFPARTMAX…ENDENDPARTICLEINJECTIONREGION:PIR1FLUID:AluminiumINJECTIONCONDITIONS:INJECTIONMETHOD:Option=Cone…NUMBEROFPOSITIONS:NumberperUnitTimeandMassFlowRate=NPARTOption=ProportionaltoMassFlowRateENDE