如何在fluent中设置多相流

如何在中设置多相流fluentvalue,or selectuser-defined to use a user-defined function.Granular Viscosity specifies thekinetic partof the granularviscosity of the particlesg,kin.You canselect constantthesdefault in the drop-down listand specify a constant value,select syamlal-obrien to compute the value,select gidaspowto compute the value,or selectuser-defined to use auser-defined function.Granular BulkViscosityspecifies the solidsbulk viscosityk.qYou canselect constantthe defaultin the drop-down listand specify a constant value,select lun-et-al tocompute thevalue,or selectuser-defined to use a user-defined function.FFictional Viscosityspecifies ashear viscositybased on the禺仃viscous-plastic flow・By default,the frictionalviscosityis neglected,as indicatedby the default selectionof noneinthe drop-down list.If you want toinclude the frictionalviscosity,you canselect constantand specify a constantvalue,select schaeffertocomputethe value,select johnson-et-al tocomputethe value,orselect user-defined to use a user-defined function.Angle ofInternal Frictionspecifies a constantvalue for theangle9used inSchaeffers expressionfor frictionalviscosity.This parameteris relevantonly if you haveselected schaefferor user-defined for the FFictionalViscosity.Frictional Pressurespecifies thepressure gradientterm,▽P in the granular-phase momentumequation.Choosefrictionynone toexclude frictionalpressure fromyour calculation,johnson-et-al,syamlal-obrien,based-ktgf wherethe frictionalpressureis definedby thekinetic theory.The solidspressuretends to a larqevalue nearthe-ackinq limit,deMiidiiiq onthemodel selectedfor theradial distributionfunction.Youmust hookauser-defined functionwhen selectingtheuser-defined option.FFictional Modulusis definedas_Q aPfriction阳/rirtGonwith G0,which is the derivedoption.You canalso specifyauser-defined functionfor the frictional modulus.Friction Packing Limit specifies a thresholdvolume fraction（开始体积分数）at whichthefrictionalregime becomesdominant.It isassumed thatfor amaximum packinglimit of

0.6,thefrictionalregime startsat avolume fractionof about

0.

5.This isonly ageneral ruleof thumbas theremay beotherfactors involved.Granular Conductivityspecifies thesolids granular（尿）conductivity・You canselect syamlal-obrien tocomputethe value,select gidaspowtocomputethevalue,or selectuser-defined touse auser-defined function.!!Note,however,that ANSYSFLUENT currentlyuses analgebraicrelation for the granular temperature.This hasbeenobtained byneglecting convectionand diffusion in thetransportequation.Granular Temperaturespecifies temperaturefor thesolidsphase andis proportionalto thekinetic energyof therandommotion of the particles.Choose eitherthe algebraic,theconstant,or user-defined option.Solids Pressurespecifies thepressure gradientterm,V P,insthe granular-phase momentumequation.Choose eitherthelun-et-al,the syamlal-obrien,the ma-ahmadi none,or auser-defined option.9Radial Distributionspecifiesacorrection factorthat modifiestheprobability ofcollisions betweengrains whenthe solidgranularphase becomesdense.Choose eitherthe lun-et-al,the syamlal-obrien,the ma-ahmadi thearastoopour,or a9user-defined option.Elasticity Modulusis definedas标G-with PackingLimit specifiesthe maximum volume fraction for thegranularphase a,max.For monodispersed spheres,thespacking limitis about

0.63,which isthe defaultvalue inANSYSFLUENT.In polydispersed cases,however,smallerspheres canfill thesmall gapsbetween largerspheres,so youmayneed toincrease themaximum packinglimit.10Click OKin the Secondary Phase dialog box.

3.

3.4Defining theInterfacial AreaConcentrationTo definethe interfacialarea concentrationon the secondaryphase in the Eulerianmodel,perform thefollowing steps:1Select the phase eg,phase-2in the Phases list.2Click Edit...to opentheSecondary Phasedialog box.3In theSecondary Phasedialog box,enter aName for thephase.4Specify whichmaterial the phase containsby choosingtheappropriate materialin the Phase Materialdrop-down list.5Define thematerial propertiesfor the Phase Material.6Enable theInterfacial AreaConcentration option.Make suretheGranular optionis disabledfor theInterfacial AreaConcentrationoption to be visiblein the interface.7In theSecondary Phasedialog box,specify thefollowingproperties of the particlesof this phase:8Diameter specifiesthe diameterof the particles orbubbles.You canselect constant in thedrop-down listand specify aconstant value,or selectuser-definedto use auser-definedfunction.See the separate UDF Manualfor detailsaboutuser-defined functions.The Diameterrecommended settingissauter-mean,allowing for the effectsof theinterfacial areaconcentrationvalues tobe consideredfor mass,momentumand heattransfer acrosstheinterfacebetween phases.9PackingLimitspecifiesthemaximumvolume fractionfor theparticle/bubble phase.10Growth Rateallows youto specify theparticlegrowth ratem/s.You canselect none,constant,or user-defined fromthedrop-down list.If youselectconstant,specifyavalue in theadjacent field.If youhave auser-defined functionUDF thatyouwant touse tomodel thegrowth rate,you canchoose theuser-defined optionand specify the appropriateUDF.11Coalescence Kernaland BreakageKernel allowsyou tospecify the coalescenceand breakage kernels.You canselectnone,constant,hibiki-ishii,ishii-kim,or user-defined.In additionto specifyingthe hibiki-ishii andishii-kim asthecoalescence andbreakagekernels,you canalso tunetheproperties of these twomodels byusing theHlld/define/phases/iac-expert/hibiki-ishii-modeltext commands./define/phases/iac-expert/ishii-kim-modelFor theHibiki-Ishii model,you canspecify thefollowingparameters:Coefficient Gamma_c Coefficient K_c,Coefficient9Gamma_b,CoefficientK_b,alpha_maxFor theIshii-Kim model,you canspecify thefollowingparameters:Coefficient Crc,Coefficient Cwe,Coefficient C,Coefficient Cti,alpha_max

3.

3.5Defining theInteraction BetweenPhases对颗粒和非颗粒流动，你必须指定在动量交换系数的计算中使用的曳力函数对颗粒流，你也必须指定颗粒碰撞的归还系数为颗粒和非颗粒流动包含可选的升力和restitution coefficients虚拟质量力下面描述也是可能的为指定这些参数，click Interaction...to openthe PhaseInteraction panel Figure

5.Specifying the Drag Functioni允许你为一对相指定曳力函数，步骤如下FLUENTa Click theDragtab to display theDrag Function inputs.对每一对相，从下面相应的列表中选择合适的曳力函数b1Select schiller-naumann touse the fluid-fluid dragfunction.The Schillerand Naumannmodel isthedefault method,and itis acceptablefor generaluse inallfluid-fluid multiphase calculations.2Select morsi-alexander touse the fluid-fluid dragfunction.The Morsiand Alexandermodel isthe mostcomplete,adjusting thefunction definitionfrequentlyover alarge rangeof Reynolds numbers,butcalculations withthis modelmay beless stablethan withtheother models.3Select symmetric touse the fluid-fluid dragfunctiondescribed.The symmetricmodel is recommended forflowsin whichthesecondarydispersed phase in oneregionof thedomain becomesthe primarycontinuousphase inanother.For example,if airis injectedinto thebottomof acontainer filledhalfway withwater,the airisthe dispersedphasein the bottomhalf of the container;in thetop halfofthecontainer,the airisthecontinuousphase.4Select wen-yu touse thefluid-solid dragfunction.TheWen andYu modelis applicablefor dilutephase flows,in whichthe totalsecondary phasevolume fractionissignificantly lowerthan thatoftheprimary phase.5Select gidaspowtouse thefluid-solid dragfunction.TheGidaspow modelis recommendedfor densefluidizedbeds.6Select syamlal-obrien tousethefluid-solid dragfunction.The Syamlal-O^rien modelisrecommendedfor useinconjunction withthe Syamlal-O^rien modelforgranular viscosity.7Select syamlal-obrien-symmetrictousethesolid-soliddrag function.The symmetricSyamlal-O*Brien modelis appropriate for a pair of solidphases.8Select constantto specifya constantvaluefor the dragfunction,and thenspecify thevalue in the text field.9Select user-defined touse auser-defined functionfor thedragfunction seethe separateUDF Manualfor details.10If youwant totemporarily ignorethe interactionbetweentwo phases,select none.Figure5:The PhaseInteraction Panelfor theEulerianModelPhase InteractionJVirtual MassDragLiR CollisionsDragCoefficientOK|Cancel|Help|Specifying theRestitution CoefficientsGranular Flow2Only对颗粒流，你必须为颗粒间的碰撞指定归还系数除了cisandess为每一对颗粒相之间的碰撞指定归还系数外，你也得为同相颗粒之间的碰撞指定归还系数步骤如下ClicktheCollisions tab todisplay the RestitutionCoefficientinputs.For eachpairof phases,specifyaconstant restitutioncoefficient.All restitutioncoefficients areequal to

0.9bydefault.Including the Lift Force3对颗粒和非颗粒流，在第二相颗粒、液滴、或气泡中包含设置般的多相流问题3Setting Upa General Multiphase Problem使用一般多相流模型的步骤

3.1Steps forUsing theGeneralMultiphase Models设置和求解一般多相流问题的步骤的要点如下，各个子部分详细的讲述在随后的章节中记住这里给出的仅是与一般多相流计算相关的步骤有关你使用的其它模型和相关的多相流模型的输入的详细信息,）将在这些模型中合适的部分给出选中你想要使用的多相流模型1（VOF,mixture,or）并指定相数EulerianDefine—Models-^Multiphase...）从材料库中复制描述每相的材料2Define-^Materials...如果你使用的材料在库中没有，应创建一种新材料!!如果你的模型中含有微粒（）相，你必须在granular materialsfluidcategory中为它创建新材料（“o/thesolid materialscategory.）））3定义相，指定相间的相互作用（interaction（例如，使用欧拉）模型时的drag functionsDefine—Phases...）（仅对欧拉模型汝口果流动是紊流，定义多相紊流模型4Define—Models—Viscous…如果体积力存在，5turn ongravity andspecify thegravitationalacceleration.Define—Operating Conditions...指定边界条件，包括第二相体积份额在流动边界和壁面上的接触角6（F Q升力H的影响是可能的这些升力作用于颗粒、液滴或气泡主要是由于主相流场中的速度梯度在大多数情形下,升力与曳力相比是不重要的，因此没必要包含它，如果升力重要（也就是说，如果相很快分离），你可以包含这个影响!!注意对大颗粒，升力更重要，但是模型假设粒子直径FLUENT远小于粒子间距离这样对接近充满的颗粒（closely）或者小颗粒，包含升力是不合适的packed particles包含升力影响的步骤如下）a ClicktheLifttabtodisplaytheLift Coefficientinputs.）对每一对相，从下面相应的列表中选择合适的指定方法b注意，既然作用于颗粒、液滴或气泡的升力主要是由于主相流场中的速度梯度，你不必为存在于两个第二相间的每对相指定升力系数；只对存在于第二相和主相之间的每对相指定升力系数Select nonethe defaultto ignorethe effectof liftforces.Select constantto specifyaconstantlift coefficient,andthen specifythevaluein thetextfield.Select user-defined touse auser-defined functionfor theliftcoefficient seetheseparateUDF Manualfor details.Including the Virtual MassForce4对颗粒和非颗粒流，当第二相相对于主相加速时包含存在的虚拟质量力是可能的当第二相的密度远小于主相的密度时虚拟质（）Rm量的影响是重要的（也就是对瞬态泡状柱流（））transient bubblecolumno包含虚拟质量力的影响，turn ontheVirtual Mass optionin thePhaseInteractionpanel.虚拟质量力的影响被包含在所有第二相内；使它仅为颗粒相是不可能的（包含体积力）Including BodyForce）5在许多情况下，相的运动部分是由于重力的影响为了包含这个体积力，应在下选择并且Operating Conditions panel Gravity指定Gravitational Acceleration.Define-^Operating Conditions...对于计算，你应当在下VOF OperatingConditionspanel下为最轻相设置密度（这种排除了水力静压的积累，提高选择并且在Specified Operating Density,Operating Density了・精度为动量平衡）如果任何一相都是可压缩roimd off的，设置为零OperatingDensity!!对于涉及体积力的和计算，建议你在VOF mixture下为选择Multiphase Model panel BodyForce Formulation.这种处理通过解决压力梯度和动量方程中体Implicit BodyForce积力的部分平衡提高了解的收敛为多相流计算选择紊流模型

3.4Eulerian如果你使用模型求解紊流，你必须在三种紊流模Eulerian型中选择一种模型在Viscous Modelpanel,Figure6o步骤如下

1.Select k-epsilon underModel.

2.Select thedesired k-epsilon Modeland anyother relatedparameters,as describedfor single-phasecalculations.

3.Under k-epsilon Multiphase Model,indicate thedesiredmultiphase turbulence model:・Select Mixturetousethe mixtureturbulence model.This isthedefaultmodel.・Select Dispersedtousethe dispersedturbulence model.This modelis applicablewhen thereis clearlyoneprimary continuousphase and the restare disperseddilutesecondary phases.・Select PerPhase tousea«turbulence modelfork-each phase.This modelisappropriatewhen theturbulencetransfer amongthe phasesplays adominantrole默认情形，相间动量,八,源项不包含在计算中如果你想包含这些源项中的任一项，你可以使用multiphase-options*包含源项Including SourceTerms注意包含COmmand in the llldlUdefine/models/viscous/multiphase-turbulence/text o这些项明显减慢收敛速度如果你要寻找额外的精度,你应首先求的没有这些源项的解，接着包含上这些源项计算大多数情形下这些源项可以忽略Figure6:The ViscousModel Panelfor anEulerianMultiphase Calculation设置边界条件

3.5多相流边界条件的设置在Boundary Conditionspanel中进行，但是设置多相流边界条件的步骤与单相流Figure7模型有些不同你必须分别为各个相设置一些条件，而其他的条件是所有相也就是所共享的，如下有详细mixture的描述混合相和各个单相的边界条件

3.

5.1Define Boundary Conditions...mixtureFigure7:The Boundary Conditions Panel如果你使用的是模型，你必须为每一个区域类型指定的Eulerian条件列举如下并总结在表和注具体的紊流参数取决于你1,2,34O使用的三个多相紊流模型，说明在表中2-4★对于如果exhaust fan,outlet vent,or pressureoutlet,你使用层流模型或使用混合紊流模型默认的多相紊流模型，没有条件为主相设置对于每个第二相，你必须设置为常数,volume fraction型线或者如果相是颗粒的你也必须设置颗UDFo granular,粒温度granular tempreture.如果你使用的混合紊流模型，你必须为指定紊流边mixture界条件；如果你使用的是分散紊流模型，你必须dispersed为主相设置它们；如果你使用的是紊流模型,你必须为主相和第二相设置它们per-phase所有其他条件都是为设置的mixture对于你必须为每一相指定速度velocity inlet,对于第二相，你必须设置如上所述volume fraction如果相是颗粒的你也必须设置颗粒温度granular,granulartemperature.如果你使用的是紊流模型，你必须为设置mixture mixture紊流边界条件；如果你使用的是分散紊流模型，你dispersed必须为主相指定它们；如果你使用的是紊流模型,你必须为主相和第二相设置它们per-phase所有其他的条件都是为设置的mixture对于所有axis,outflow,periodic,solid,or symmetryzone,条件都是为设置的；没有条件为单相设置mixture对于条件为单相指定；所有其他条件为wall zone,shear指定mixture对于所有和都是为fluid zone,source termsfixed values单相设置的，除非你使用的是紊流模型或mixture dispersed紊流模型如果你使用的是紊流模mixture型，紊流的source terms和fixed values为mixture设置；如果你使用的是紊流模型，他们只为主相设置dispersed如果不是多孔的，所有其他条件都是为fluid zone设置mixture如果是多孔的，你将为混合相选择在fluid zonePorous Zone面板下也是为混合相指Fluid Porosityinputsif relevant定的而和Resistance coefficientsdirection分别为每一相指定所有其他条件都是为混合vectors相指定的注边界pressure far-field,fan,porous jumpand radiator在使用模型时是无效的EulerianTable1:Phase-Specific andMixture Conditionsfor theEulerianModel forLaminar FlowTypePrimary Secondary Phase MixturePhaseexhaust fan nothingvolume fraction;all othersoutlet vent gran.temperaturepressure outletinletvent coord.coord,system;dir.spec,system;intake fanflow directionflow direction;method;mass flow inlet volume fraction;all othersgran,pressure inlettemperaturevelocity inlet velocity velocity;all othersvolume fraction;gran,temperatureaxis nothingnothing allothersoutflowperiodicsolidsymmetryshearwall shearcondition allothersconditionpressurenot availablenot availablenot availablefar-fieldfanporous jumpradiatorfluidall sourceall sourceterms;porousterms;zone;all fixedallfixed values;porosity;values;other porousother porousall othersinputs inputsTable2:Phase-Specific andMixture Conditionsfor theEulerianModel withthe MixtureTurbulence ModelPrimaryTypeMixtureSecondary PhasePhaseexhaustfan nothing all othersvolume fraction;outlet ventgran.temperaturepressure outletinletvent coord,system;dir.spec.coord.system;intake fanflow direction;method;flow directionall othersmass flow inlet volume fraction;pressure inletgran,temperaturevelocity inlet velocityvelocity;all othersvolumefraction;gran,temperatureaxis nothingnothing allothersoutflowperiodicsolidsymmetryshearwall shearcondition allothersconditionpressurenot availablenot availablenot availablefar-fieldfan）设置模拟具体的解参数Define-^Boundary Conditions…7Solve-Controls TSohition…）初始化解和为第二相设定初始体积份额8Solve-^Initialize—Patch...）计算求解和检查结果9欧拉多相流模拟的附加指南（AdditionalGuidelines for）Eulerian MultiphaseSimulations一旦你决定了欧拉多相流模型适合你的问题,你应当考虑求解你的多相流问题的需求计算能力要求的计算能力很强的依赖于所求解的输运方程的个数和耦合程度对欧拉多相流模型，有大数量的高度耦合的输运方程，计算的耗费将很高,在设置你的问题前，尽可能减少问题的到最简化的可能形式statement在你开始第一次求解尝试，取而代之尽力去求解多相流动的所有的复杂方面，你可以以简单近似地开始并且知道问题定义的最终形式简化多相流问题的一些建议列举如下使用六面体或四边形网格（而不用四面体或三角形网格）减少相的数目

2.你会发现即使简单的近似也会给你的问题提供有用的信porous jumpradiatorfluidother sourceother sourcesource termsterms;terms;for turbulence;other fixedother fixedfixed valuesvalues;values;for turbulence;other porousother porousporous zone;inputsinputsporosity;all othersTable3:Phase-Specific andMixture Conditionsfor theEulerianModel withthe DispersedTurbulence ModelTypePrimary Phase Secondary MixturePhaseexhaustfanturb.volume allothersparameters fraction;outletventgran.temperaturepressure outletinletvent coord,system;coord,system;dir.spec.intake fanflow direction;flow direction;methodturb.all othersmassflowinletparameters;volumefraction;gran,pressure inlettemperaturevelocityinletvelocity;velocity;all othersturb.volumefraction;parametersgran,temperatureaxis nothingnothing allothersoutflowperiodicsolidsymmetrywall shearcondition shearcondition allotherspressurenot availablenot availablenotavailablefar-fieldfanporous jumpradiatorfluidmomentum andmomentum,porous zone;mass,turb.sources;mass sources;porosity;momentum andall othersmomentum,mass,turb.fixed massfixedvalues;values;other porousother porousinputsinputsTable4:Phase-Specific andMixture Conditionsfor theEulerianModel withthe Per-Phase TurbulenceModelType Primary PhaseSecondaryMixturePhaseexhaust fanall othersturb.volumefraction;parametersoutlet ventturb.parameters;gran,pressure outlettemperatureinletvent coord,system;coord,system;dir.spec.intake fanflow direction;flow direction;method;turb.allothersmassflowinletvolumefraction;parameterspressure inletturb.parameters;gran,temperaturevelocityinletvelocity;velocity;all othersturb.volumefraction;parametersturb.parameters;gran,temperatureaxis nothingnothingallothersoutflowperiodicsolidsymmetrywall shearcondition shearcondition allotherspressurenot availablenotavailablenotfar-fieldavailablefanporous jumpradiatorfluidmomentum,momentum,porous zone;mass,mass,turb.sources;turb.sources;porosity;all othersmomentum,momentum,mass,mass,turb.fixed turb.fixedvalues;values;other porousother porousinputsinputs设置边界条件的步骤你需要给每一个边界执行的步骤如下:）在面板的列表中选择边界;1BoundaryConditionsZone）如果必要，在这个边界上为设置条件（见上述2mixture有关的需要为设置条件的信息）mixturea In thePhase drop-down list,select mixture.b Ifthe currentType for this zoneis correct,click Set...to openthe correspondingpanele.g.the Pressure5Inlet panel;otherwise,choose thecorrect zonetype intheType list,confirm thechangewhen prompted,andthe correspondingpanel will open automatically.c In the correspondingpanel for the zonetype youhave・，selected eg・the PressureInlet panel,shown inFigure8,specifythe mixture boundary conditions.Figure8:The PressureInlet Panelfor aMixture注仅仅那些适用于所有相的条件，如上所述，将出现在这个面板中!!对于计算，如果你在面板中VOF PhaseInteraction选择了你能在上指定接触角为每一对Wall Adhesion,wall）相接触角（

0.就是壁面和接触面切线的夹角,量度了在面板的成对的列表中第一相的值例Wall如，如果你设置和相的接触角在面板中,il airWall量度在相内对于所有对默认值是度，就是Oo oil90没有壁面支持的影响（也就是，接触面垂直于支持面）例如，接触角为度，相当于水沿着容器面爬行，通常是水在45玻璃上d Click OK when you aredone settingthe mixtureboundary conditions.）如果必要，在这个边界上为每一相设置条件（上述有关3必要为每一相设置条件的信息）a In thePhasedrop-down list,select the phase eg,water.!!注意当你选择了单相中的一个而不是只有一类mixture,区域出现在列表中在给定的边界上是不可能指定Type行类的，这种区域类型是为指定phase.sped czone mixture的，它也适用于所有的单相b Click Set...to openthe panelforthisphases conditions・eg”the PressureInlet panel,shown inFigure

9.Figure9:The PressureInlet Panelfor aPhasePressure InletZoneName Phasepressure-iniet-4waterX-Component ofFlow Direction1V-Component ofFlow DirectionVolume Fraction0OK CancelHelpc Specify the conditions for the phase.Note thatonlythose conditionsthat applyto theindividual phase,asdescribed above,will appearin thispanel.d Click OK whenyou aredone settingthephase-specificboundary conditions.复制边界条件的步骤为多相流动复制边界条件的步骤与在中描述的为单相流动的有些不同修改的步骤如下1In theBoundaryConditionspanel,click the Copy...button Thiswill opentheCopyBCs panel.2In the From Zone list,select thezone thathas theconditionsyouwant to copy.3In theTo Zones list,select thezone orzones towhich youwantto copy the conditions.4In thePhasedrop-down list,select thephase forwhich youwantto copythe conditionseither mixtureor oneof theindividualphases.!!Note thatcopying theboundary conditionsfor onephasedoes notautomatically resultin theboundaryconditionsforthe otherphases and the mixturebeing copiedas well.Youneed tocopytheconditionsforeach phaseon eachboundaryof interest.5Click Copy.FLUENT willset ofthe selectedphases orallmixturesboundaryconditionsonthezones selected in theToZoneslisttobethe sameas thatphases conditionsonthe zoneselectedin theFromZonelist.You cannotcopy asubsetoftheconditions,such asonly thethermalconditions.设置初始容积比率

3.6一旦你初始化了流动,你就as describedin section

22.13能定义相的初始分布对于瞬态模拟，这个分布将作为初始条件在仁时刻；对于稳态模拟，设置初始分布在计算的早期阶段能0提供更多的稳定性）你可以使用面板为第二相修订（初始容积Patch patch比率Solve—Initialize—Patch...如果你想修订容积比率的区域已经作为隔离的单元区被定义，你只能修订那个地方的值否则，你可以创建一个包括合适单元的“寄存器”并在这个寄存器中修订值欧拉模型的求解策略4Solution Strategiesfor theEulerian ModelCalculatingan InitialSolution为了提高收敛性，在求解完整欧拉多相流模型前你可以先获得初始解有两种方法你可以用来为欧拉多相流计算获得初始解:启动和求解问题用混合模型（选或不选滑流速度都

3.可）代替欧拉模型然后启动欧拉模型，完成设置，采用混合模型的解作为起点继续计算通常启动欧拉多相流计算，但是仅计算主相的流动

4.这样做时，在的下面不Solution Controlspanel Equations选一旦你为主相获得了初始解，打开VolumeFraction.volume方程继续为各相计算fraction!!注意没有获得用混合模型或欧拉模型作为欧拉多相流模型的初始解，你不应该使用单相解这样做，不能提高收敛性，可能会给流动的收敛带来更多的困难选用多相流模型并指定相数

3.2Enabling theMultiphaseModeland Specifyingthe Number of Phases为了选多相流模型，在VOF,mixture,Eulerian Multiphase下选ModelpanelVolume ofFluid,Mixture,or Eulerianas theModeLDefine—Models-^Multiphase...如果你选的欧拉模型，输入如下.number ofphases为了给多相流计算指定相数，在下输入合适的值你最多可以指定NumberofPhases20相.optional cavitationeffects包含气穴影响IncludingCavitation Effects对混合的欧拉模型计算，包含气穴影响是可能的为了选气穴模型，在中MultiphaseModelpanel InterphaseMass下打开Transfer Cavitation由于气穴影响，接下来你应指定在使用传质计算时的两个参数这些参数的指定应当于调查下的流动特征参数相一致:在Reynoldsnumberand cavitationnumber MultiphaseModelo中下面，设置panel CavitationParameters VaporizationPressurePv和Bubble NumberDensityQ〃的默认值是10000,由推荐默认的值是环境温度下水的汽化Kubota etal Pv

2367.8,压力Temporarily IgnoringLift andVirtualMassForces如果你计划在稳态欧拉多相流模拟中包含升力和虚拟质量力，你经常减弱问题的稳定性，这有时发生在计算的早期阶段，是由于暂时忽略了升力和虚拟质量力引起的一旦没有这些力的解开始收敛，你可以打断计算，合适地定义这些力,继续计算一般多相流问题的后处理5Postprocessing GeneralMultiphase Problems三种一般的多相流模型中的每一种都提供了一些你能画图和汇报的附加的场函数你也可以汇报流动比率为三种模型中单个相，为混合模型和欧拉计算中每一相显示速度矢量可用的后处理变量

5.1Available PostprocessingVariables当你使用其中的一种一般多相流模型模型时，几个附加的场函数对后处理好是有用的，这里列举如下对欧拉模型的计算你可以产生如下所列项目的图象显示和数据汇报:・Volume fractionof phase-n in the Phases...category・Density ofphase-n in the Density...category・phase-n Velocity Magnitude in the Velocity...category・phase-n RelativeVelocityMagnitudein the Velocity...category・phase-n X,Y,Z,etc.Velocity in the Velocity...category・phase-n RelativeY,Z,etc.Velocity in the Velocity...X,category・phase-n StreamFunction intheVelocity...category・phase-n TurbulentViscosity inthe Turbulence...category・phase-n WallYplus inthe Turbulence...category・phase-n TurbulentKinetic EnergyintheTurbulence...category・phase-n TurbulentDissipation RateintheTurbulence...category・phase-n Productionof kintheTurbulence...category・Molecular Viscosityofphase-ninthe Properties...category・Diameter ofphase-ninthe Properties...category・phase-n WallShear StressintheWall Fluxes...category・phase-n X,Y,Z WallShear StressintheWall Fluxes...category・phase-n SkinFriction CoefficientintheWall Fluxes...categoryThe availabilityoftheturbulence quantitieslisted abovewilldepend onwhich multiphaseturbulencemodelyou usedinthe calculation.!!注意如果你读一个多相数据文件给在画Eulerian FLUENT,图和汇报上面所列项目前你必须运行进行一次迭代当你正用计算时画图和汇报这Solver FLUENT些变量，这是不必要的显示单相的速度矢量

5.2Display VelocityVectors for Individual Phases对混合和欧拉计算，使用显示单相的速度矢量是可能Vector panel的Display—Vectors…为了显示特殊相的速度矢量，在下拉列表中选Vector Ofphase-n这里被感兴趣相的名字所代替，例如，Velocity phase-n air-bubbles你也可选Velocity oRelative phase-n Velocity来显示相对于移动参考体系的相的速度为了显示混合相速度以仅与混合模型的计算相关，选择Velocity orRelativeVelocity forthemixturevelocity relativetoamoving referenceframe.报告单相的流量

5.3Report FluxesforIndividualPhase当你使用计算通过边界的流量时，你应该指出Fhix Reportspanel报告是对混合相的还是对单相的Report-^Fluxes...选择在下拉列表中在面板底部来报告混合相流量，mixture Phase或者选择相的名字来报告所选相的流量报告单相在壁面上的力

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8.4Reporting Forceson WallsforIndividual Phase对欧拉计算，当你使用来计算力或壁面Force Reportspanel边界上的动量时，你应当指定你想要为之计算力的单相Report—Forces…在面板左边的下拉列表中选择你所要选的相的名字Phase报告单相的流量比率

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8.5Reporting FlowRates forIndividualPhase你可以使用命令来获得每一相（或混report/massfow text合相）通过每一流动边界上的质量流量比率report-^mass-flow当你指定感兴趣的相（混合相或者单相），将列出每个区FLUENT域，区域后面跟着是所指定相质量流率所通过的区域举例如下:/report mfmixturewater airdomainid/name[mixture]airzone10spiral-press-outlet:-

1.2330244zone3pressure-outlet:-

9.7560663zone11spiral-vel-inlet:

0.6150589zone8spiral-wall:0zone1walls:0zone4velocity-inlet:

4.9132133net mass-flow:-

5.4608185定义相概述

3.3Overview ofDefining thePhases为了定义相包括它们的材料属性和相间的相互作用例如，欧拉模型中的曳力函数，你将使用Phases panelFigure

1.Define—Phases...Figure1:The PhasesPanel这个面板中下的每一项两类之一，如在列表Phase Type中所示指出了所选项是主相，primary-phase secondary-phase指出所选项是第二相指定相之间的相互作用，点击Interaction...button.定义主相

3.

3.1Defining thePrimary Phase!!通常，你可以你喜欢的任何方式指定主相和第二相考虑你的选择如何影响问题的设置是一种很好的主意，特别是在复杂的问题中例如，对区域一部分中的一相，如果你计划其初始体积份额为patch L指定这个相为第二相更方便同样，如果一相是可压缩的，为了提高解的稳定性，建议你指定它为主相!!记住，只能有一相是可压缩的确定你没有选择可压缩材料（也就是对密度使用可压缩理想气体定律的材料）为多于一相的1Select phase-1inthePhase list.2Click Set...,and thePrimary Phase panelFigure2will open.Figure2:The Primary Phase Panel3In thePrimaryPhasepanel,enter aName forthephase.4Specify whichmaterial thephase containsby choosingtheappropriate materialinthePhase Materialdrop-down list.5Define thematerial propertiesforthePhase Material.Click Edit...,and theMaterial panelwillopen.In theMaterial panel,check theproperties,and modifythemif necessary.!!If youmake changesto theproperties,remember toclickChange beforeclosing theMaterial panel.6ClickOKinthePrimaryPhasepanel.定义非颗粒即液体或气体第二相

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3.2Defining aNon-Gramilar Secondary Phase1Select thephase e.g”phase-2inthePhase list.2Click Set...,andtheSecondary PhasepanelFigure3willopen.Figure3:The Secondary Phase Panelfor aNon-GranularPhaseSecondary PhaseOK|Cancel!Help|3In theSecondary Phasepanel,enter aName forthephase.4Specify whichmaterial thephase containsby choosingtheappropriate materialinthePhase Materialdrop-down list.5Define thematerial propertiesforthePhase Material,following thesame procedureyou usedto setthe materialpropertiesfortheprimary phase.6IntheSecondary Phasepanel,specifytheDiameter ofthebubbles ordroplets of thisphase.You canspecifyaconstantvalue,oruseauser-defined function.See theseparateUDFManualfor detailsabout user-definedfunctions.7ClickOKintheSecondaryPhasepanel.定义颗粒第二相

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3.3Defining aGranular SecondaryPhase1Select thephase eg,phase-2inthePhase list.2ClickSet...,andtheSecondaryPhasepanelFigure4willopen.3IntheSecondaryPhasepanel,enter aName forthephase.4Specify whichmaterial thephase containsby choosingtheappropriate materialinthePhase Materialdrop-down list.5Define thematerial propertiesforthePhase Material,following thesame procedureyou usedto setthe materialpropertiesfortheprimary phase.For agranular phasewhichmust beplaced inthefluidmaterials category.!!You needto specifyonly thedensity;you canignore thevaluesfortheother properties,since theywill notbe used.Inthe SecondaryPhasepanel.6Enable theGranular option.7optional Enablethe PackedBed optionifyouwanttofreezethe velocityfield forthe granularphase._!!Note thatwhenyouselect thepacked bedoption fora行phase,you shouldalso usethe xedvelocity optionwith avalueof zerefor allvelocity componentsfor allinterior cellzonesfor thatphase.8SpecifytheGranular TemperatureModel.Choose eitherthedefault PhaseProperty optionorthePartial DifferentialEquationoption.Figure4:The SecondaryPhase PanelforaGranularPhase9IntheSecondaryPhasedialogbox,specifythefollowingproperties ofthe particlesofthisphase:Diameter specifiesthe diameteroftheparticles.You canselectconstantinthedrop-down listandspecifyaconstant。