This chapter presents the concepts, processes, and commands that describe the thermal radiation specific attributes of heat transfer analysis problems being modeled in the Patran System. Most of this chapter deals with preprocess model building in Patran.

The concept of radiation enclosure is specific to thermal radiation analysis and is described in Radiation Enclosure Concept, 25. The concept of surface orientation, while not unique to thermal radiation analysis, has not been introduced previously in MSC.Software Corporation thermal analysis tools, and is described in Surface Orientation in Patran, 31. Specifying Radiation Boundary Conditions Using Patran Reference Manual (VFAC Boundary Condition), 38 and Advanced Features of the VFAC Boundary Condition, 42 deal with identifying the radiative boundary conditions and other associated information using the Patran Radiation Boundary condition.

Relationship of VFAC LBC Data to VFINDAT File Data, 51 explains the relationship of the Viewfactor LBC form to the data in the VFINDAT input data file for Viewfactor. Patran Thermal TEMPLATEDAT Files for Surface Property Description, 52 and Compatibility Requirements for Model and VFAC Templates, 65 discuss the Patran Thermal TEMPLATEDAT file and the associated VFAC template data. In the last section of this chapter, page 67, the role of symmetry in thermal radiation problems is discussed. The method for specifying the existence and type of symmetry in a problem is presented.

Some sophisticated thermal analysis tools have been provided and thus this chapter contains a large amount of information. Take the time to understand all of the capabilities of the tools available here. This will enable you to make informed decisions regarding how to model the thermal radiation phenomena at hand and choose the appropriate tools for the analysis.

You must understand the concept of radiation enclosure, Radiation Enclosure Concept, 25. If you wish to model materials or media with wavelength dependent properties, then Surface Orientation in Patran, 31 must be understood. Specifying Radiation Boundary Conditions Using Patran Reference Manual (VFAC Boundary Condition), 38 deals with basic radiative boundary conditions, while Advanced Features of the VFAC Boundary Condition, 42 deals with move advanced features that enable modeling of participating media, radiation to ambient nodes, and methods for reducing CPU time required for a Viewfactor analysis.

If you are also responsible for the accompanying Patran Thermal analysis, then Patran Thermal TEMPLATEDAT Files for Surface Property Description, 52 andCompatibility Requirements for Model and VFAC Templates, 65 regarding the TEMPLATEDAT files and VFAC templates are strongly recommended. Be cautious using symmetry in thermal radiation problems, since the thermal radiation boundary conditions have subtle ways of making what appears to be a symmetric problem actually nonsymmetric. However, if you must make use of symmetry, Symmetry as Applied to the Model and Viewfactor Radiation Exchange, 67 should be thoroughly mastered.