SteadyState Thermal（稳态热）PPT课件下载推荐.pptx

1、Thermal Analysis,Chapter Six,ANSYS Workbench Si,Training Manual,Thermal Analysis,Chapter Overview,In this chapter,performing steady-state and transient thermal analyses in Simulation will be covered:#,GeometryAssemblies Solid Body ContactHeat LoadsSolution OptionsResults and PostprocessingWorkshop 6

2、.1Thermal Transient SetupTransient SettingsTransient LoadsTransient ResultsWorkshop 6.2,The capabilities described in this section are generally applicable to ANSYS DesignSpace Entra licenses and above,except for an ANSYS Structural license.,Training Manual,Thermal Analysis,Basics of Steady-State He

3、at Transfer,For a steady-state（static）thermal analysis in Simulation,the temperatures T are solved for in the matrix below:#Assumptions:#No transient effects are considered in a steady-state analysisK can be constant or a function of temperatureQ can be constant or a function of temperatureANSYS Wor

4、kbench Si,Training Manual,Thermal Analysis,Basics of Steady-State Heat Transfer,Fouriers Law provides the basis of the previous equation:#Heat flow within a solid（Fouriers Law）is the basis of KHeat flux,heat flow rate,and convection are treated as boundary conditions on the system QConvection is tre

5、ated as a boundary condition although temperature-dependent film coefficients are possibleIt is important to remember these assumptions relAaNteSdYtSo Workbench Siperforming thermal analyses in Simulation.,ANSYS Workbench Si,Training Manual,Thermal Analysis,Physics Filters,If a thermal-only solution

6、 is to be performed the Physics Filter can be used to filter the GUIUnder“View menu Physics Filter,”unselect the“Structural”and“Electromagnetic”optionsThis applies to options in the“Environment”and“Solution”levels only,If a thermal-stress simulation is to be performed,do not turn,off the structural

7、physics filter,Training Manual,Thermal Analysis,A.Geometry,In thermal analyses,all types of bodies supported by Simulation may be used.Solid,surface,and line bodies are supportedFor surface bodies,thickness must be input in the Details view of the Geometry branchLine bodie cross-section and orientat

8、ion is defined within DesignModeler,Cross-section and orientation information results inAaNnSYS Workbench Si,effective thermal cross-section Only temperature results are available for line bodies The“Point Mass”feature is not available in thermal analyses,Training Manual,Thermal Analysis,Geometry,Sh

9、ell and line body assumptions:#For shell bodies through-thickness temperature gradients are not available.Shells assume temperatures on top and bottom of surface are the sameFor line bodies through thickness variation in the temperature is not available.Line bodies assume the temperature is constant

10、 across the cross-sectionTemperature variation will still be considered along the line bodyANSYS Workbench Si,ANSYS Workbench Si,Training Manual,Thermal Analysis,Material Properties,Thermal Conductivity is input in the Engineering Data applicationTemperature-dependent thermal conductivity is input a

11、s a table,If any temperature-dependent material properties exist,this will result in a nonlinear solution.,The only required material property is thermal conductivity,ANSYS,Workbench Si,Training Manual,Thermal Analysis,B.Assemblies Solid Body Contact,When importing assemblies of solid parts,contact

12、regions are automatically created between the solid bodies enabling heat transfer between parts in an assembly,Model shown is from a sample Inventor assembly.,Training Manual,Thermal Analysis,Assemblies Contact Region No heat spreading is considered in the contact/target interface,Heat flow within t

13、he contact region is in the contact normal direction onlyHeat flows only if a target element is present in the normal direction of a contact element,In the figure on the left,the solid,green double-aArroNwsSinYdiScateWorkbench Siheat flow within the contactregion.Heat flow only occurs if a target su

14、rface is normal to a contact surface.The light,dotted green arrows indicate that no heat transfer will occur between parts.,Training Manual,Thermal Analysis,Assemblies Contact Region,If the parts are initially in contact heat transfer will occur between the parts.If the parts are initially out of co

15、ntact no heat transfer takes placeSummary:#,ANSYS Workbench Si The pinball region determines when contact occurs and is automatically defined and set to a relatively small value to accommodate small gaps in the model,ANSYS Workbench,Si,Training Manual,Thermal Analysis,Assemblies Contact Region,If th

16、e contact is bonded or no separation,then heat transfer will occur（solid green lines）when the surfaces are within the pinball radius,In this figure on the right,the gap between the two parts is bigger than the pinball region,so no heat transfer will occur between the parts,Pinball Radius,ANSYS Workbench Si,Training Manual,Thermal Analysis,Assemblies Thermal Conductance The amount of heat flow between two parts is defined by the contact heat flux q:#,where Tcontact is the temperature of a contact“node”a