PAT312, Section 60, December 2006 S60-1 Copyright 2007 MSC.Software Corporation SECTION 60 PATRAN RADIATION LBCS

PAT312, Section 60, December 2006 S60-2 Copyright 2007 MSC.Software Corporation

PAT312, Section 60, December 2006 S60-3 Copyright 2007 MSC.Software Corporation MSC.PATRAN RADIATION LBCS l Gap Radiation l User input form factor l Does not invoke viewfactor computation l Valid for form factor approaching 1.0 l View factor radiation l View factors calculated by MSC.Patran l Automatically added to the resistor network l MSC.Patran can also write Trasys and Nevada input files

PAT312, Section 60, December 2006 S60-4 Copyright 2007 MSC.Software Corporation GAP RADIATION l Creates radiation resistors from nodes in the Application Region to those in the Companion Region l Closest Approach and Select algorithms for connection to Companion Region l Area is nodal element sub-area in Application Region

PAT312, Section 60, December 2006 S60-5 Copyright 2007 MSC.Software Corporation GAP RADIATION BOUNDARY CONDITIONS l Open Loads/BCs Application l Set Object to Radiation l Set Option to Gap Radiation l Select Appropriate Target and Region 2 dimensionality

PAT312, Section 60, December 2006 S60-6 Copyright 2007 MSC.Software Corporation GAP RADIATION LBC INPUT DATA l Fixed l Input data consists of l Application surface emissivity l Coupling surface emissivity l User input form factor l A spatial field can be used for any or all of these inputs

PAT312, Section 60, December 2006 S60-7 Copyright 2007 MSC.Software Corporation GAP RADIATION LBC INPUT DATA l Uncheck Fixed l Input data consists of Material Property IDs for: l Application surface emissivity l Coupling surface emissivity l User input form factor l MPIDs selected from previously created material property fields l Time dependent l Temperature dependent

PAT312, Section 60, December 2006 S60-8 Copyright 2007 MSC.Software Corporation GAP RADIATION LBC APPLICATION REGION l Use all Geometry or all FEM l Resistor areas are based on Application Region l Closest approach is most general and robust l Every node in the Application Region has a resistor connected to it l Selected Point/Node requires 1-1 correspondence

PAT312, Section 60, December 2006 S60-9 Copyright 2007 MSC.Software Corporation VIEW FACTOR FEATURES AND CAPABILITIES l Organized by Enclosures l Convex surface flag l Collapse and obstruction flags l Symmetry operators l Waveband dependency supported

PAT312, Section 60, December 2006 S60-10 Copyright 2007 MSC.Software Corporation VIEW FACTOR BOUNDARY CONDITIONS On the Top Menu bar when you click on Load/BCs, the MSC.Thermal Load/Boundary Conditions form is displayed Set the options to Template, View Factor View Factor Boundary Condition can only be applied as Element Uniform Type Target element types are 1D, 2D, 3D

PAT312, Section 60, December 2006 S60-11 Copyright 2007 MSC.Software Corporation VIEW FACTOR INPUT DATA Enter an Enclosure ID Enter VFAC Template ID. This is a pointer into the template.dat.apnd file (VFAC Template) Radiation to ambient can be modeled with an ambient node, Ambient Node ID If the medium is participating radiatively enter the Participating Media Node ID. To this node you may assign the bulk temperature of the participating medium. If a surface cannot see itself, you can speed up view factor calculation by flagging such a surface with a convex surface ID. Surfaces with same Convex Surface ID wont be able to see each other.

PAT312, Section 60, December 2006 S60-12 Copyright 2007 MSC.Software Corporation SURFACE ORIENTATION l Viewfactor analysis requires a well defined and consistent surface normal orientation l In 2-D Planar and 2-D Axisymmetric Models the user must verify this l 2D Planar - Element Normals must be in the +Z direction l 2D Axisymmetric - Element Normals must be in the RxZ direction l In 3D General models, the normal direction is consistent with top selection in the viewfactor LBC form

PAT312, Section 60, December 2006 S60-13 Copyright 2007 MSC.Software Corporation SURFACE APPLICATION REGION l Top matches element normal direction

PAT312, Section 60, December 2006 S60-14 Copyright 2007 MSC.Software Corporation EXAMPLE VFAC TEMPLATE l TID = 99 l Emissivity = 0.89 l Comment lines start with * l Create using Analysis/Build Template

PAT312, Section 60, December 2006 S60-15 Copyright 2007 MSC.Software Corporation VIEW FACTOR JOB CONTROL

PAT312, Section 60, December 2006 S60-16 Copyright 2007 MSC.Software Corporation RUN CONTROL PARAMETERS l Run Control corresponds to Viewfactor solution type l 0 = Viewfactors Resistors l 1 = Viewfactors Only l 2 = Resistors Only l Convergence Criteria l Default (-1.0) controls convergence based on: l Converg = 0.01 / (# surfaces in enclosure)^0.7 l Zero l Cutoff value l Viewfactors below cutoff are set to zero

PAT312, Section 60, December 2006 S60-17 Copyright 2007 MSC.Software Corporation RUN CONTROL PARAMETERS (Cont.) l Approx Curve l Controls subdivisions of curved surface for obstruction checking l Gauss Order, Contour Integration (default, 8) l Applies to contour integration around boarder of surface l Gauss Order, Double Area (default, 8) l Applies to area integration for partially obstructed viewfactors l Gauss Order, FE Weighting (default, 8) l Applies to surface-to-surface weighting of viewfactors according to FE interpolation functions l Min/Max Axisymmetric subdivisions l Controls the effective subdivisions of the 3D image of an axisymmetric surface

PAT312, Section 60, December 2006 S60-18 Copyright 2007 MSC.Software Corporation

PAT312, Section 60, December 2006 S60-19 Copyright 2007 MSC.Software Corporation

PAT312, Section 60, December 2006 S60-20 Copyright 2007 MSC.Software Corporation