稳态热分析案例（ANSYS 150版）

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本例题的主要部分为一个圆筒形罐，其上沿径向有一材料一样的接纳（如图？？？？所所示），罐内滚动着450°F（232°C）的高温流体，接纳内滚动着100°F（38°C）的低温流体，两个流体区域由薄壁管隔离。罐的对流换热系数为250Btu/hr-ft2-oF（1420watts/m2-°K），接纳的对流换热系数随管壁温度而变，它的热物理性能如表？？？所示。要求计算罐与接纳的温度分布。表？？？？

温度密度导热系数比热708.352008.904053009.353524009.8275500oF3o0.2850.2850.2850.2850.285lb/in10.23Btu/hr-ft-Fo0.1130.1170.1190.1220.125Btu/lb-F221Btu/hr-ft-F2o对流换热系数426

6.5.1预处理

Step1:确定分析标题

起动ANSYS后，开始一个分析，需要输入一个标题，按下面方法进行操作：1.选择UtilityMenu>File>ChangeTitle，弹出相应对话框2.输入Steady-statethermalanalysisofpipejunction。3.点击OK。Step2:设置分析单位系统

Youneedtospecifyunitsofmeasurementfortheanalysis.Forthispipejunctionexample,measurementsusetheU.S.Customarysystemofunits(basedoninches).

Tospecifythis,typethecommand/UNITS,BINintheANSYSInputwindowandpressENTER.在分析之前，需要为分析系统设定单位系统，Step3:DefinetheElementType

Theexampleanalysisusesathermalsolidelement.Todefineit,dothefollowing:1.ChooseMainMenu>Preprocessor>ElementType>Add/Edit/Delete.TheElementTypesdialogboxappears.

2.ClickonAdd.TheLibraryofElementTypesdialogboxappears.

3.Inthelistontheleft,scrolldownandpick(highlight)\listontheright,pick\4.ClickonOK.

5.ClickonClosetoclosetheElementTypesdialogbox.Step4:DefineMaterialProperties

Todefinematerialpropertiesfortheanalysis,performthesesteps:

1.ChooseMainMenu>Preprocessor>MaterialProps>MaterialModels.TheDefineMaterialModelBehaviordialogboxappears.

2.IntheMaterialModelsAvailablewindow,double-clickonthefollowingoptions:Thermal,Density.Adialogboxappears.

3.Enter.285forDENS(Density),andclickonOK.MaterialModelNumber1appearsintheMaterialModelsDefinedwindowontheleft.

4.IntheMaterialModelsAvailablewindow,double-clickonthefollowingoptions:Conductivity,Isotropic.Adialogboxappears.

5.ClickontheAddTemperaturebuttonfourtimes.Fourcolumnsareadded.6.IntheT1throughT5fields,enterthefollowingtemperaturevalues:70,200,300,400,and500.Selecttherowoftemperaturesbydraggingthecursoracrossthetextfields.ThencopythetemperaturesbypressingCtrl-c.

7.IntheKXX(ThermalConductivity)fields,enterthefollowingvalues,inorder,foreachofthetemperatures,thenclickonOK.Notethattokeeptheunitsconsistent,eachofthegivenvaluesofKXXmustbedividedby12.YoucanjustinputthefractionsandhaveANSYSperformthecalculations.

8.35/128.90/129.35/129.80/1210.23/12

8.IntheMaterialModelsAvailablewindow,double-clickonSpecificHeat.Adialogboxappears.

9.ClickontheAddTemperaturebuttonfourtimes.Fourcolumnsareadded.

10.WiththecursorpositionedintheT1field,pastethefivetemperaturesbypressingCtrl-v.

11.IntheC(SpecificHeat)fields,enterthefollowingvalues,inorder,foreachofthetemperatures,thenclickonOK.

.22.125

12.ChoosemenupathMaterial>NewModel,thenenter2forthenewMaterialID.ClickonOK.MaterialModelNumber2appearsintheMaterialModelsDefinedwindowontheleft.

13.IntheMaterialModelsAvailablewindow,double-clickonConvectionorFilmCoef.Adialogboxappears.

14.ClickontheAddTemperaturebuttonfourtimes.Fourcolumnsareadded.15.WiththecursorpositionedintheT1field,pastethefivetemperaturesbypressingCtrl-v.

16.IntheHF(FilmCoefficient)fields,enterthefollowingvalues,inorder,foreachofthetemperatures.Tokeeptheunitsconsistent,eachvalueofHFmustbedividedby144.Asinstep7,youcaninputthedataasfractionsandletANSYSperformthecalculations.426/144405/144352/144275/144

221/144

17.ClickontheGraphbuttontoviewagraphofFilmCoefficientsvs.temperature,thenclickonOK.

18.ChoosemenupathMaterial>ExittoremovetheDefineMaterialModelBehaviordialogbox.

19.ClickonSAVE_DBontheANSYSToolbar.Step5:DefineParametersforModeling

1.ChooseUtilityMenu>Parameters>ScalarParameters.TheScalarParameterswindowappears.

2.Inthewindow'sSelectionfield,enterthevaluesshownbelow.(Donotenterthetextinparentheses.)PressENTERaftertypingineachvalue.Ifyoumakeamistake,simplyretypethelinecontainingtheerror.

RI1=1.3(Insideradiusofthecylindricaltank)

RO1=1.5(Outsideradiusofthetank)

Z1=2(Lengthofthetank)RI2=.4(Insideradiusofthepipe)RO2=.5(Outsideradiusofthepipe)

Z2=2(Lengthofthepipe)3.ClickonClosetoclosethewindow.Step6:CreatetheTankandPipeGeometry

1.ChooseMainMenu>Preprocessor>Modeling>Create>Volumes>

Cylinder>ByDimensions.TheCreateCylinderbyDimensionsdialogboxappears.

2.Setthe\the\fieldto90.3.ClickonOK.

4.ChooseUtilityMenu>WorkPlane>OffsetWPbyIncrements.TheOffsetWPdialogboxappears.

5.Setthe\6.ClickonOK.

7.ChooseMainMenu>Preprocessor>Modeling>Create>Volumes>

Cylinder>ByDimensions.TheCreateCylinderbyDimensionsdialogboxappears.

8.Setthe\the\fieldto-90andthe\9.ClickonOK.

10.ChooseUtilityMenu>WorkPlane>AlignWPwith>GlobalCartesian.Step7:OverlaptheCylinders

1.ChooseMainMenu>Preprocessor>Modeling>Operate>Booleans>Overlap>Volumes.TheOverlapVolumespickingmenuappears.2.ClickonPickAll.

Step8:ReviewtheResultingModel

Beforeyoucontinuewiththeanalysis,quicklyreviewyourmodel.Todoso,followthesesteps:

1.ChooseUtilityMenu>PlotCtrls>Numbering.ThePlotNumberingControlsdialogboxappears.

2.ClicktheVolumenumbersradiobuttontoOn,thenclickonOK.

3.ChooseUtilityMenu>PlotCtrls>ViewSettings>ViewingDirection.Adialogboxappears.

4.Setthe\5.Reviewtheresultingmodel.

6.ClickonSAVE_DBontheANSYSToolbar.Step9:TrimOffExcessVolumes

Inthisstep,deletetheoverlappingedgesofthetankandthelowerportionofthepipe.1.ChooseMainMenu>Preprocessor>Modeling>Delete>VolumeandBelow.TheDeleteVolumeandBelowpickingmenuappears.

2.Inthepickingmenu,type3,4andpresstheENTERkey.ThenclickonOKintheDeleteVolumeandBelowpickingmenu.Step10:CreateComponentAREMOTE

Inthisstep,youselecttheareasattheremoteYandZedgesofthetankandsavethemasacomponentcalledAREMOTE.Todoso,performthesetasks:

1.ChooseUtilityMenu>Select>Entities.TheSelectEntitiesdialogboxappears.