ANSYS130理论参考手册

1、Release 13.0 - © 2010 SAS IP, Inc. All rights reserved.Table of Contents1. Analyzing Thermal Phenomena1.1. How ANSYS Treats Thermal Modeling. Convection. Radiation. Special Effects. Far-Field Elements1.2. Types of Thermal Analysis1.3. Coupled-Field Analyses1.4. About GUI Paths and Command Synta

2、x2. Steady-State Thermal Analysis2.1. Available Elements for Thermal Analysis2.2. Commands Used in Thermal Analyses2.3. Tasks in a Thermal Analysis2.4. Building the Model. Using the Surface Effect Elements. Creating Model Geometry2.5. Applying Loads and Obtaining the Solution. Defining the Analysis

3、Type. Applying Loads. Using Table and Function Boundary Conditions. Specifying Load Step Options. General Options. Nonlinear Options. Output Controls. Defining Analysis Options. Saving the Model. Solving the Model2.6. Reviewing Analysis Results. Primary data. Derived data. Reading In Results. Review

4、ing Results2.7. Example of a Steady-State Thermal Analysis (Command or Batch Method). The Example Described. The Analysis Approach. Commands for Building and Solving the Model2.8. Performing a Steady-State Thermal Analysis (GUI Method)2.9. Performing a Thermal Analysis Using Tabular Boundary Conditi

5、ons. Running the Sample Problem via Commands. Running the Sample Problem Interactively2.10. Where to Find Other Examples of Thermal Analysis3. Transient Thermal Analysis3.1. Elements and Commands Used in Transient Thermal Analysis3.2. Tasks in a Transient Thermal Analysis3.3. Building the Model3.4.

6、Applying Loads and Obtaining a Solution. Defining the Analysis Type. Establishing Initial Conditions for Your Analysis. Specifying Load Step Options. Nonlinear Options. Output Controls3.5. Saving the Model. Solving the Model3.6. Reviewing Analysis Results. How to Review Results. Reviewing Results wi

7、th the General Postprocessor. Reviewing Results with the Time History Postprocessor3.7. Reviewing Results as Graphics or Tables. Reviewing Contour Displays. Reviewing Vector Displays. Reviewing Table Listings3.8. Phase Change3.9. Example of a Transient Thermal Analysis. The Example Described. Exampl

8、e Material Property Values. Example of a Transient Thermal Analysis (GUI Method). Commands for Building and Solving the Model3.10. Where to Find Other Examples of Transient Thermal Analysis4. Radiation4.1. Analyzing Radiation Problems4.2. Definitions4.3. Using LINK31, the Radiation Link Element4.4.

9、Modeling Radiation Between a Surface and a Point4.5. Using the AUX12 Radiation Matrix Method. Procedure. Recommendations for Using Space Nodes. General Guidelines for the AUX12 Radiation Matrix Method4.6. Using the Radiosity Solver Method. Procedure. Further Options for Static Analysis4.7. Advanced

10、Radiosity Options4.8. Example of a 2-D Radiation Analysis Using the Radiosity Method (Command Method). The Example Described. Commands for Building and Solving the Model4.9. Example of a 2-D Radiation Analysis Using the Radiosity Method with Decimation and Symmetry (Command Method). The Example Desc

11、ribed. Commands for Building and Solving the ModelRelease 13.0 - © 2010 SAS IP, Inc. All rights reserved.Chapter 1: Analyzing Thermal PhenomenaA thermal analysis calculates the temperature distribution and related thermal quantities in a system or component. Typical thermal quantities

12、 of interest are: · The temperature distributions· The amount of heat lost or gained· Thermal gradients· Thermal fluxes.Thermal simulations play an important role in the design of many engineering applications, including internal combustion engines, turbines, heat exchangers, pip

13、ing systems, and electronic components. In many cases, engineers follow a thermal analysis with a stress analysis to calculate thermal stresses (that is, stresses caused by thermal expansions or contractions).The following thermal analysis topics are available:· How ANSYS Treats Thermal Modelin

14、g· Types of Thermal Analysis· Coupled-Field Analyses· About GUI Paths and Command Syntax1.1. How ANSYS Treats Thermal ModelingOnly the ANSYS Multiphysics, ANSYS Mechanical, ANSYS Professional, and ANSYS FLOTRAN programs support thermal analyses.The basis for thermal analysis in A

15、NSYS is a heat balance equation obtained from the principle of conservation of energy. (For details, consult the Theory Reference for the Mechanical APDL and Mechanical Applications.) The finite element solution you perform via ANSYS calculates nodal temperatures, then uses the nodal temperatures to

16、 obtain other thermal quantities.The ANSYS program handles all three primary modes of heat transfer: conduction, convection, and radiation. ConvectionYou specify convection as a surface load on conducting solid elements or shell elements. You specify the convection film coefficient and the bulk

17、 fluid temperature at a surface; ANSYS then calculates the appropriate heat transfer across that surface. If the film coefficient depends upon temperature, you specify a table of temperatures along with the corresponding values of film coefficient at each temperature.For use in finite element models

18、 with conducting bar elements (which do not allow a convection surface load), or in cases where the bulk fluid temperature is not known in advance, ANSYS offers a convection element named LINK34. In addition, you can use the FLOTRAN CFD elements to simulate details of the convection process, such as

19、 fluid velocities, local values of film coefficient and heat flux, and temperature distributions in both fluid and solid regions. RadiationANSYS can solve radiation problems, which are nonlinear, in four ways: · By using the radiation link element, LINK31· By using surface effect elem

20、ents with the radiation option (SURF151 in 2-D modeling or SURF152 in 3-D modeling)· By generating a radiation matrix in AUX12 and using it as a superelement in a thermal analysis.· By using the Radiosity Solver method.For detailed information on these methods, see Radiation. Special

21、EffectsIn addition to the three modes of heat transfer, you can account for special effects such as change of phase (melting or freezing) and internal heat generation (due to Joule heating, for example). For instance, you can use the thermal mass element MASS71 to specify temperature-dependent heat

22、generation rates. Far-Field ElementsFar-field elements allow you to model the effects of far-field decay without having to specify assumed boundary conditions at the exterior of the model. A single layer of elements is used to represent an exterior sub-domain of semi-infinite extent. For more i

23、nformation, see Far-Field Elements in the Low-Frequency Electromagnetic Analysis Guide.1.2. Types of Thermal AnalysisANSYS supports two types of thermal analysis: 1. A steady-state thermal analysis determines the temperature distribution and other thermal quantities under steady-state loading c

24、onditions. A steady-state loading condition is a situation where heat storage effects varying over a period of time can be ignored.2. A transient thermal analysis determines the temperature distribution and other thermal quantities under conditions that vary over a period of time.1.3. Coupled-F

25、ield AnalysesSome types of coupled-field analyses, such as thermal-structural and magnetic-thermal analyses, can represent thermal effects coupled with other phenomena. A coupled-field analysis can use matrix-coupled ANSYS elements, or sequential load-vector coupling between separate simulations of

26、each phenomenon. For more information on coupled-field analysis, see the Coupled-Field Analysis Guide.1.4. About GUI Paths and Command SyntaxThroughout this document, you will see references to ANSYS commands and their equivalent GUI paths. Such references use only the command name, because you

27、 do not always need to specify all of a command's arguments, and specific combinations of command arguments perform different functions. For complete syntax descriptions of ANSYS commands, consult the Command Reference.The GUI paths shown are as complete as possible. In many cases, choosing the

28、GUI path as shown will perform the function you want. In other cases, choosing the GUI path given in this document takes you to a menu or dialog box; from there, you must choose additional options that are appropriate for the specific task being performed.For all types of analyses described in this

29、guide, specify the material you will be simulating using an intuitive material model interface. This interface uses a hierarchical tree structure of material categories, which is intended to assist you in choosing the appropriate model for your analysis. See Material Model Interface in the Basic Ana

30、lysis Guide for details on the material model interface.Release 13.0 - © 2010 SAS IP, Inc. All rights reserved.Chapter 2: Steady-State Thermal AnalysisThe ANSYS Multiphysics, ANSYS Mechanical, ANSYS FLOTRAN, and ANSYS Professional products support steady-state thermal analysis. A stea

31、dy-state thermal analysis calculates the effects of steady thermal loads on a system or component. Engineer/analysts often perform a steady-state analysis before performing a transient thermal analysis, to help establish initial conditions. A steady-state analysis also can be the last step of a tran

32、sient thermal analysis, performed after all transient effects have diminished.You can use steady-state thermal analysis to determine temperatures, thermal gradients, heat flow rates, and heat fluxes in an object that are caused by thermal loads that do not vary over time. Such loads include the foll

33、owing: · Convections· Radiation· Heat flow rates· Heat fluxes (heat flow per unit area)· Heat generation rates (heat flow per unit volume)· Constant temperature boundariesA steady-state thermal analysis may be either linear, with constant material properties; or nonline

34、ar, with material properties that depend on temperature. The thermal properties of most material do vary with temperature, so the analysis usually is nonlinear. Including radiation effects also makes the analysis nonlinear.The following steady-state thermal analysis topics are available:· Avail

35、able Elements for Thermal Analysis· Commands Used in Thermal Analyses· Tasks in a Thermal Analysis· Building the Model· Applying Loads and Obtaining the Solution· Reviewing Analysis Results· Example of a Steady-State Thermal Analysis (Command or Batch Method)· Perf

36、orming a Steady-State Thermal Analysis (GUI Method)· Performing a Thermal Analysis Using Tabular Boundary Conditions· Where to Find Other Examples of Thermal Analysis2.1. Available Elements for Thermal AnalysisThe ANSYS and ANSYS Professional programs include about 40 elements (descri

37、bed below) to help you perform steady-state thermal analyses.For detailed information about the elements, see the Element Reference, which manual organizes element descriptions in numeric order.Element names are shown in uppercase. All elements apply to both steady-state and transient thermal analys

38、es. SOLID70 also can compensate for mass transport heat flow from a constant velocity field.Table 2.1  2-D Solid ElementsElementDimens.Shape or CharacteristicDOFsPLANE352-DTriangle, 6-nodeTemperature (at each node)PLANE552-DQuadrilateral, 4-nodeTemperature (at each node)PLANE752-DHarm

39、onic, 4-nodeTemperature (at each node)PLANE772-DQuadrilateral, 8-nodeTemperature (at each node)PLANE782-DHarmonic, 8-nodeTemperature (at each node)Table 2.2  3-D Solid ElementsElementDimens.Shape or CharacteristicDOFsSOLID703-DBrick, 8-nodeTemperature (at each node)SOLID873-DTetrahedr

40、on, 10-nodeTemperature (at each node)SOLID903-DBrick, 20-nodeTemperature (at each node)SOLID2783-DBrick, 8-nodeTemperature (at each node)SOLID2793-DBrick, 20-nodeTemperature (at each node)Table 2.3  Radiation Link ElementsElementDimens.Shape or CharacteristicDOFsLINK312-D or 3-DLine,

41、2-nodeTemperature (at each node)Table 2.4  Conducting Bar ElementsElementDimens.Shape or CharacteristicDOFsLINK333-DLine, 2-nodeTemperature (at each node)Table 2.5  Convection Link ElementsElementDimens.Shape or CharacteristicDOFsLINK343-DLine, 2-nodeTemperature (at eac

42、h node)Table 2.6  Shell ElementsElementDimens.Shape or CharacteristicDOFsSHELL1313-DQuadrilateral, 4-nodeMultiple temperatures (at each node)SHELL1323-DQuadrilateral, 8-nodeMultiple temperatures (at each node)Table 2.7  Coupled-Field ElementsElementDimens.Shape or Chara

43、cteristicDOFsPLANE132-DThermal-structural, 4-nodeTemperature, structural displacement, electric potential, magnetic vector potentialFLUID1163-DThermal-fluid, 2-node or 4-nodeTemperature, pressureSOLID53-DThermal-structural and thermal-electric, 8-nodeTemperature, structural displacement, electric po

44、tential, and magnetic scalar potentialSOLID983-DThermal-structural and thermal-electric, 10-nodeTemperature, structural displacement, electric potential, magnetic vector potentialLINK683-DThermal-electric, 2-nodeTemperature, electric potentialSHELL1573-DThermal-electric, 4-nodeTemperature, electric

45、potentialTARGE1692-DTarget segment elementTemperature, structural displacement, electric potentialTARGE1703-DTarget segment elementTemperature, structural displacement, electric potentialCONTA1712-DSurface-to-surface contact element, 2-nodeTemperature, structural displacement, electric potentialCONT

46、A1722-DSurface-to-surface contact element, 3-nodeTemperature, structural displacement, electric potentialCONTA1733-DSurface-to-surface contact element, 4-nodeTemperature, structural displacement, electric potentialCONTA1743-DSurface-to-surface contact element, 8-nodeTemperature, structural displacem

47、ent, electric potentialCONTA1752-D/3-DNode-to-surface contact element, 1 nodeTemperature, structural displacement, electric potentialPLANE2232-DThermal-structural, thermal-electric, structural-thermoelectric, and thermal-piezoelectric, 8-nodeTemperature, structural displacement, electric potentialSO

48、LID2263-DThermal-structural, thermal-electric, structural-thermoelectric, and thermal-piezoelectric, 20-nodeTemperature, structural displacement, electric potentialSOLID2273-DThermal-structural, thermal-electric, structural-thermoelectric, and thermal-piezoelectric, 10-nodeTemperature, structural di

49、splacement, electric potentialTable 2.8  Specialty ElementsElementDimens.Shape or CharacteristicDOFsMASS711-D, 2-D, or 3-DMass, one-nodeTemperatureCOMBIN371-DControl element, 4-nodeTemperature, structural displacement, rotation, pressureSURF1512-DSurface effect element, 2-node to 4-no

50、deTemperatureSURF1523-DSurface effect element, 4-node to 9-nodeTemperatureMATRIX501Matrix or radiation matrix element, no fixed geometry1INFIN9 2 2-DInfinite boundary, 2-nodeTemperature, magnetic vector potentialINFIN47 2 3-DInfinite boundary, 4-nodeTemperature, magnetic vector potentialINFIN110 2 2

51、-DInfinite boundary, 4 or 8 nodesTemperature, magnetic vector potential, electric potentialINFIN111 2 3-DInfinite boundary, 8 or 20 nodesTemperature, magnetic scalar potential, magnetic vector potential, electric potentialCOMBIN141-D, 2-D, or 3-DCombination element, 2-nodeTemperature, structural dis

52、placement, rotation, pressureCOMBIN391-DCombination element, 2-nodeTemperature, structural displacement, rotation, pressureCOMBIN401-DCombination element, 2-nodeTemperature, structural displacement, rotation, pressure1. As determined from the element types included in this superelement.2. For inform

53、ation on modeling the effects of far-field decay, see Far-Field Elements in the Low-Frequency Electromagnetic Analysis Guide.2.2. Commands Used in Thermal AnalysesExample of a Steady-State Thermal Analysis (Command or Batch Method) and Performing a Steady-State Thermal Analysis (GUI Method) sho

54、w you how to perform an example steady-state thermal analysis via command and via GUI, respectively. For detailed, alphabetized descriptions of the ANSYS commands, see the Command Reference.2.3. Tasks in a Thermal AnalysisThe procedure for performing a thermal analysis involves three main tasks

55、: · Build the model.· Apply loads and obtain the solution.· Review the results.The next few topics discuss what you must do to perform these steps. First, the text presents a general description of the tasks required to complete each step. An example follows, based on an actual steady

56、-state thermal analysis of a pipe junction. The example walks you through doing the analysis by choosing items from ANSYS GUI menus, then shows you how to perform the same analysis using ANSYS commands.2.4. Building the ModelTo build the model, you specify the jobname and a title for your analy

57、sis. Then, you use the ANSYS preprocessor (PREP7) to define the element types, element real constants, material properties, and the model geometry. (These tasks are common to most analyses. The Modeling and Meshing Guide explains them in detail.)For a thermal analysis, you also need to keep these po

58、ints in mind: · To specify element types, you use either of the following: Command(s): ETGUI: Main Menu> Preprocessor> Element Type> Add/Edit/Delete · To define constant material properties, use either of the following: Command(s): MPGUI: Main Menu> Preprocessor> Material Props> Material Models> Thermal· The material properties can be input as numerical values or as table inputs for some elements. Tabular material properties are calculated before the first iteration (i.e., using initial val