icepak-meshing-网格划分解析

E-1Meshing5.MeshingE-2先进的网格技术Fullyautomatic完全自动化的网格生成Localandglobalcontrols局部和总体控制HexahedralorTetrahedralmeshes六面体/四面体先进的非结构化网格先进的non-conformalmeshIcepakautomaticmeshing:OverviewE-3TwoHexahedralmeshersUnstructuredCartesianTetrahedralmesher专门使用于somecomplexgeometryMustbeusedforellipsoids,ellipticalcylinders,orpolygonalductingIcepakautomaticmeshing:OverviewE-4•Allthemethodsarefullyautomated•可以进行不同复杂程度的网格划分NoparameterssetParametersdefinedonanobjectbyobjectbasis•Aftermeshing,Icepakchecksthekeyqualitymeasure.Iftherearecellswithpoorquality,Icepakwillautomaticallydisplaythem.•TheKeymeasuresare:FaceAlignmentforHexahedral(面扭曲率)AspectRatioforTetrahedral(长宽比)AutomaticmeshingE-5usex,y,zcount对物体进行划分设定物体周围的LowandHighelementsize/ratioInwardheight/ratiotorefinewithinanobjectsetMaxX,Y,ZsizesExaminemeshusing物体的surfaceplotsandcutplanesdefaultoptionswithMaxX,Y,Zsetto1/10thor1/20thofdomainsizeRefinetheMeshExaminetheMeshSolveGeneratenewMeshYesNoRe-examinetheMeshOK?Meshingstepsandconsiderations•Usecoarsemeshforinitialsolutions•UsesuitablyrefinedmeshforfinalsolutionE-6TwoHexahedralMeshersUnstructured-MeshwillfollowthegeometryCartesian-六面体单元组成的structuredmesh-对非矩形几何模型划分Stair-step(阶梯状)approximationsHexahedralmeshingE-7台阶状近似几何不正确的几何面积远场网格不得不加密网格数量多，精度差真实几何正确的几何面积只在需要的地方加密网格网格数量少，精度好结构化网格非结构化网格HexahedralmeshingE-8Hexahedralmeshing:structuredandunstructuredE-9GlobalSettings-forrefiningmeshDefaultSettings-meshertype,backgroundmeshsettings包括generate,Display,Checkquality,andExportHexahedralmeshing:GenerationpanelE-10MesherTypeHexa-Unstructured,Hexa-Cartesian,Tetrahedral,mesher-hd(hex-dominantmesher六面体核心网格)只有六面体核心网格才能对CADobjects进行网格划分MaxX,MaxY,MaxZControlthesizeofthelargestcellallowableinthebackgroundmeshObjectParamsIndividualparametersDefaultsettingsE-11MaxX,Y,ZBydefaultthisis1/20thofthecabinetdimensions1/10thofthedomainsizeissufficientforacoarsegrid不推荐使用小于1/20thdomainsize,可能生成大量不必要的网格InitHeightRecommendedthatyoudonotsetthisonlargemodelsasitcanresultinverylargemeshcountsRecommendationsE-12NormalMesher–ProvidesanacceptablemeshformostsituationsCoarseMesher–ProvidesacoarsemeshMesherdefaultsettingsinclude:Minelementsinfluidgap-MinimumnumberofcellsinbetweenadjacentfacesMinelementsonsolidedge-MinimumnumberofcellstobeplacedontheedgeofanobjectMaxO-gridheight-MaximumheightoftheO-gridregionfromthesurfaceofanobjectMinelementsinfluidgap=2Minelementsinfluidgap=3Globalsettings(1)E-13MaximumSizeRatio可以控制网格尺寸的增长速度TheGrowthratioofelementsawayfromsurfacescanbecontrolledusingthissetting.Dx2/Dx1MaxsizeRatiosettingSolidregionFluidRegionDx2Dx3Dx1Globalsettings(2)E-14MinelementsoncylinderfaceMinelementsontrianglefaceAdditionalOptionalFlagsNo“O”gridPrevents“O”meshingonallobjectsMeshassembliesseparately选择它，Icepak将对assemblies创建non-conformalandputafinermeshontheobjectswithintheassemblyGlobalsettings(3)E-15MinelementsinfluidgapEither2or3Morethan4mayrefinethemeshinunwantedregionsMaxSizeratioBetween2and10Max“O”gridheightDefaultsettingof0meansthatthereisnocontroloftheheightofthecut-outregionRecommendedtosetareasonable“O”-gridheightRecommendationsE-16可以对指定的物体设置网格参数.Usesinclude:Controllingthemeshdensityaroundobjects以捕捉thermal/flowgradientsEnterarequestedvalueNote:细画时:–Meshcountmustbegreaterthancurrentvalue–HeightsorratiosmustbelessthancurrentvalueUsingper-objectparametersE-17RectangularPrismobjects-e.g.:Block/ResistanceX,Y,ZcountLow/HighX,Y,Zheight第一个网格的高度awayfromandobjectLow/HighX,Y,ZratioGrowthofaspectratioawayfromanobjectInwardheight/ratioHeight/growthoffirstcellintoanobjectPer-objectparameters:RectangulargeometryE-18Rectangularplanarobjects-e.g.Rectangularvent,PCB,Plateetc...X&Y,Y&Z,X&ZcountLow/HighendheightHeightoffirstcelleithersideofplanarobjectLow/HighendratiogrowthrateeithersideofobjectInwardheight/ratioHeight/growthofcellsintotheobjectPer-objectparameters:RectangulargeometryE-19圆板objects-e.g.fanetc…Additionalsettingsare:Diametercount–NumberofcellsacrossthediameterLow/HighEndheightsandratiosPer-objectparameters:CirculargeometryE-20CircularCylindricalObjects-e.g.汽缸etc…Additionalsettingsare:DiametercountSidecount–Numberofelementsalongthecurvedsurfaceofthecylinder等等Per-objectparameters:CirculargeometryE-21Displaymesh:surface/volume/solid/cutplaneoptionsCutplanelocation/meshcolorScreenselectoptionsforcutplaneChangethecolorofthemeshontheplanecutViewingthemeshE-22Aspectratio（长宽比）Ratioofshortestlengthtothelongestlength–shouldbepositivepreferablyabove0.01FaceAlignment（面的扭曲度）Rangefrom0(bad)to1(good)Shouldbeabove0.15Facealignmentindex=c0c1•fc0c1fQualitymeasuresforhexahedralmeshE-23可以改变最大值Thenclickreplot-eg:setMaxto0.15,可以看到面扭曲比比较差的网格Canalsochangethenumberofbarsinthehistogram.clickonthegreenhistogrambar,将看到这个范围的网格UsingqualitydiagnosticsE-24DisplayingcellsE-25Thetetrahedralmesher一般用在非常复杂的几何模型中如果模型中包含一些小尺寸的物体时(suchasthinplates),采用四面体网格划分将导致网格数很大TetrahedralmesherE-26Globalmeshercontrols:Maxtetrasize:Smoothmesh:activatesasmoothing运算toimprovemeshqualityobjectparams:specifiesmeshparametersforindividua