fluent中多孔介质设置问题和算例Word格式文档下载.doc
- 文档编号:15268662
- 上传时间:2022-10-29
- 格式:DOC
- 页数:21
- 大小:909KB
fluent中多孔介质设置问题和算例Word格式文档下载.doc
《fluent中多孔介质设置问题和算例Word格式文档下载.doc》由会员分享,可在线阅读,更多相关《fluent中多孔介质设置问题和算例Word格式文档下载.doc(21页珍藏版)》请在冰豆网上搜索。
1)定义矢量:
二维定义一个矢量,第二个矢量方向不用定义,是与第一个矢量方向正交的;
三维定义二个矢量,第三个矢量方向不用定义,是与第一、二个矢量方向正交的;
(如何知道矢量的方向:
打开grid图,看看X,Y,Z的方向,如果是X向,矢量为1,0,0,同理Y向为0,1,0,Z向为0,0,1,如果所需要的方向与坐标轴正向相反,则定义矢量为负)
圆锥坐标与球坐标请参考fluent帮助。
2)定义粘性阻力1/a与内部阻力C2:
请参看本人上一篇博文“终于搞清fluent中多孔粘性阻力与内部阻力的计算方法”,此处不赘述;
3)如果了定义粘性阻力1/a与内部阻力C2,就不用定义C1与C0,因为这是两种不同的定义方法,C1与C0只在幂率模型中出现,该处保持默认就行了;
4)定义孔隙率porousity,默认值1表示全开放,此值按实验测值填写即可。
完了,其他设置与普通k-e或RSM相同。
总结一下,与君共享!
Tutorial7.ModelingFlowThroughPorousMedia
Introduction
Manyindustrialapplicationsinvolvethemodelingofflowthroughporousmedia,suchasfilters,catalystbeds,andpacking.Thistutorialillustrateshowtosetupandsolveaprobleminvolvinggasflowthroughporousmedia.
Theindustrialproblemsolvedhereinvolvesgasflowthroughacatalyticconverter.Catalyticconvertersarecommonlyusedtopurifyemissionsfromgasolineanddieselenginesbyconvertingenvironmentallyhazardousexhaustemissionstoacceptablesubstances.
Examplesofsuchemissionsincludecarbonmonoxide(CO),nitrogenoxides(NOx),andunburnedhydrocarbonfuels.Theseexhaustgasemissionsareforcedthroughasubstrate,whichisaceramicstructurecoatedwithametalcatalystsuchasplatinumorpalladium.
Thenatureoftheexhaustgasflowisaveryimportantfactorindeterminingtheperformanceofthecatalyticconverter.Ofparticularimportanceisthepressuregradientandvelocitydistributionthroughthesubstrate.HenceCFDanalysisisusedtodesignefficientcatalyticconverters:
bymodelingtheexhaustgasflow,thepressuredropandtheuniformityofflowthroughthesubstratecanbedetermined.Inthistutorial,FLUENTisusedtomodeltheflowofnitrogengasthroughacatalyticconvertergeometry,sothattheflowfieldstructuremaybeanalyzed.
Thistutorialdemonstrateshowtodothefollowing:
_Setupaporouszoneforthesubstratewithappropriateresistances.
_Calculateasolutionforgasflowthroughthecatalyticconverterusingthepressurebasedsolver.
_Plotpressureandvelocitydistributiononspecifiedplanesofthegeometry.
_Determinethepressuredropthroughthesubstrateandthedegreeofnon-uniformityofflowthroughcrosssectionsofthegeometryusingX-Yplotsandnumericalreports.
ProblemDescription
ThecatalyticconvertermodeledhereisshowninFigure7.1.Thenitrogenflowsinthroughtheinletwithauniformvelocityof22.6m/s,passesthroughaceramicmonolithsubstratewithsquareshapedchannels,andthenexitsthroughtheoutlet.
Whiletheflowintheinletandoutletsectionsisturbulent,theflowthroughthesubstrateislaminarandischaracterizedbyinertialandviscouslosscoefficientsintheflow(X)direction.Thesubstrateisimpermeableinotherdirections,whichismodeledusinglosscoefficientswhosevaluesarethreeordersofmagnitudehigherthanintheXdirection.
SetupandSolution
Step1:
Grid
1.Readthemeshfile(catalyticconverter.msh).
File/Read/Case...
2.Checkthegrid.Grid/Check
FLUENTwillperformvariouschecksonthemeshandreporttheprogressintheconsole.Makesurethattheminimumvolumereportedisapositivenumber.
3.Scalethegrid.
Grid!
Scale...
(a)SelectmmfromtheGridWasCreatedIndrop-downlist.
(b)ClicktheChangeLengthUnitsbutton.Alldimensionswillnowbeshowninmillimeters.
(c)ClickScaleandclosetheScaleGridpanel.
4.Displaythemesh.Display/Grid...
(a)Makesurethatinlet,outlet,substrate-wall,andwallareselectedintheSurfacesselectionlist.
(b)ClickDisplay.
(c)RotatetheviewandzoomintogetthedisplayshowninFigure7.2.
(d)ClosetheGridDisplaypanel.
Thehexmeshonthegeometrycontainsatotalof34,580cells.
Step2:
Models
1.Retainthedefaultsolversettings.Define/Models/Solver...
2.Selectthestandardk-εturbulencemodel.Define/Models/Viscous...
Step3:
Materials
1.AddnitrogentothelistoffluidmaterialsbycopyingitfromtheFluentDatabaseformaterials.Define/Materials...
(a)ClicktheFluentDatabase...buttontoopentheFluentDatabaseMaterialspanel.
i.Selectnitrogen(n2)fromthelistofFluentFluidMaterials.
ii.ClickCopytocopytheinformationfornitrogentoyourlistoffluidmaterials.
iii.ClosetheFluentDatabaseMaterialspanel.
(b)ClosetheMaterialspanel.
Step4:
BoundaryConditions.Define/BoundaryConditions...
1.Settheboundaryconditionsforthefluid(fluid).
(a)SelectnitrogenfromtheMaterialNamedrop-downlist.
(b)ClickOK
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- fluent 多孔 介质 设置 问题