WORKSHOP 11 USING CONVECTION CORRELATIONS

WS11-2 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation

WS11-3 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Model Description In this exercise you will determine the steady state temperature distribution in an iron cube (MID 18). The temperature distribution will be driven by a heat flux on one vertical face, natural convection on another vertical face, and forced convection on the top horizontal face. CONV definitions link convection Template IDs (TIDs) which are applied in the Loads/BCs form to convection configurations and associated Material Property IDs (MPIDs). CONV definitions for air will be placed in a mat.dat.apnd which you will copy from an examples directory. The mat.dat.apnd file is placed in the same directory as your database. MSC.Patran contains an extensive library of convection coefficient configurations. The configurations are described in Chapter 9, Volume 1 of the MSC.Thermal Application Module User Manual. This volume can be accessed through the on- line Help/ Document Library…

WS11-4 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Objectives Model an iron cube. Apply convective boundary conditions using correlations from the MSC.Thermal convection correlation library. Run a steady state analysis and display results.

WS11-5 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Exercise Overview 1. Create a new database named exercise_11.db. Set Tolerance to Default, and the Analysis Code to MSC/THERMAL. 2. Create a 1m x 1m solid. 3. Mesh the solid with an IsoMesh of Hex8 elements, Global Edge Length of Use Finite Elements/Create/Node/Edit to create a boundary node not associated with geometry. 5. Apply element properties to the Hex8 elements defining them as Thermal 3D Solid and having a Material Name (MID) of Create a spatial field which will provide distance-from-the-leading-edge data to the convection coefficient calculation. 7. Define a fixed temperature and heat flux boundary condition in Loads/BCs. 8. Define two convection boundary conditions assigning each a different Convection Template ID and supplying the distance from the leading edge in the Convection Coefficient data box. 9. Use the new Analysis/Build Template form to create a template.dat.apnd containing the CONV definitions. 10. In your xterm window (shell) and in the directory which contains the database, use get_qtran to copy an existing file, mat.dat.apnd, containing air MPID data in your directory. 11. Prepare and submit the model for analysis specifying that it is a steady state, that all calculations and output should be°K, and that all eight columns of nodal results are included in the nodal results file. 12. Read and plot the results. 13. Quit MSC.Patran.

WS11-6 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 1: Create a New Database Create a new database called exercise_11.db. a. File / New. b. Enter exercise_11 as the file name. c. Click OK. d. Choose Default Tolerance. e. Select MSC.Thermal as the Analysis Code. f. Select Thermal as the Analysis Type. g. Click OK. a bc d e f g

WS11-7 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 2: Create Solid Geometry Create a 1m x 1m x 1m solid. a. Geometry. b. Create/Solid/XYZ. c. Enter for Vector Coordinate List. d. Apply. e. Select Viewing. f. Click Named View Options… g. Select isometric_view for Select Named View. h. Close. a b c d e

WS11-8 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 3: IsoMesh the Solid IsoMesh the solid with Hex8 solid elements. a. Finite Elements. b. Create/Mesh/ Solid. c. Select Hex under Elem Shape d. Select IsoMesh as Mesher e. Select Solid 1 for Solid List. f. Turn off Automatic Calculation g. Enter 0.1 for Value h. Apply. a b e f g h c d

WS11-9 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 4: Create a Boundary Sink Node Use Finite Elements: Create/Node/Edit to create a boundary node, Node 9999, not associated with geometry. a. Finite Elements. b. Create/Node/ Edit. c. Enter 9999 for Node ID List. d. Unselect Associate with Geometry. e. Enter [ ] for Node Location List. f. Apply. g. Increase node size by clicking Display. h. Select Finite Elements… i. Using the slider bar select 6 for Node Size. j. Apply. k. Cancel. a c b d e f g Node 9999

WS11-10 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 5: Apply Element Properties Apply element properties to the Hex8s defining them as Thermal 3D Solid elements. a. Properties. b. Create/3D/ Thermal 3D Solid. c. Enter Prop1 for Property Set Name. d. Click on Input Properties… e. Enter 18 for Material Name. f. OK. g. Select Solid 1 for Select Members. h. Add. i. Apply. a e f b c d g i h Note: for forced convection boundary conditions the heat transfer coefficient varies as the thermal boundary layer develops from the leading edge. One input to the convective correlation is the distance from the leading edge of the surface. MSC.Patran Thermal provides for spatial fields to define the element distance from the leading edge. Create a spatially varying field that will define the required distance.

WS11-11 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 6: Create the Field for the Distance Create a spatial field which will provide the distance from the leading edge of the surface. This is for calculating the convection coefficient. a. Fields. b. Create/Spatial/PCL Function. c. Enter X_dist for Field Name. d. Enter X for Scalar Function. e. Apply. a b c d e

WS11-12 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 7: Create a Fixed Temperature Boundary Condition Create a boundary condition for a fixed temperature. a. Loads/BCs. b. Create/Temperature/ Nodal. c. Set Option to Fixed. d. Enter Tamb for New Set Name. e. Click Input Data… f. Enter for Fixed Temperature. g. OK. h. Click on Select Application Region… i. Select the FEM filter. j. Select Node 9999 for Select Nodes. k. Add. l. OK. m. Apply. a b c d e f g h i j l m k

WS11-13 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 8: Define Heat Flux Loading Apply heat loading to the left facing (-X direction) face/surface of the solid. a. Loads/BCs. b. Create/Heating/ Element Uniform. c. Select Flux, Fixed for Option. d. Enter Flux for New Set Name. e. Enter 3D for Target Element Type. f. Click Input Data… g. Enter 1000 for Fixed Heat Flux. h. OK. i. Click Select Application Region… j. Click on the Geometry Filter. k. Select Solid 1.1 for Select Solid faces. l. Add. m. OK. n. Apply. a b c d e f g h i j k m n l

WS11-14 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 9: Define two Convection Boundary Conditions Define two convection boundary conditions. One is forced and the other is natural convection. a. Loads/BCs. b. Create/Convection/ Element Uniform. c. Set Option to Template, Convection. d. Enter forced_convection for New Set Name. e. Select 3D for Target Element Type. f. Click Input Data… g. Deselect Fixed. h. Click Select Spatial Field… i. Under Spatial Fields select X_dist. j. Enter 93 for Convection Template ID. k. Select Node 9999 for Fluid Node ID. l. OK. a b c d e f g h i j k l

WS11-15 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 9: Define two Convection Boundary Conditions (Cont.) Continue to define the two convection boundary conditions. One is forced and the other is natural convection. a. Click Select Applications Region… b. Select the Geometry Filter. c. Select the top face (+Y direction) of Solid 1, Solid 1.4, for Select Solid Faces. d. Add. e. OK. f. Apply. g. Repeat these steps for New Set Name natural_convection. h. Click in the CONV GP2/GP3 databox, and leave it blank. i. Use Convection Template ID of 913, and Fluid Node Node j. In Select Applications Region select the right face (+X direction) of Solid 1, Solid 1.2, for Select Solid Faces. k. Click Apply b c e d

WS11-16 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 10: View Loads and Boundary Conditions Using Utilities Can review the loads and boundary conditions using Utilities. a. Click on Utilities. b. Select Thermal. c. Select Thermal BC Display… d. Select OK when the disclaimer appears e. Apply. f. Clear, to clear the Utilities markers from the display. g. Close, to close this form. a b c g fe

WS11-17 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 11: Create template.dat.apnd File Use the Analysis: Build Template form to create the template.dat.apnd file containing the CONV definitions. a. Analysis. b. Build Template. c. Click on Create Template File… d. Set to Create/CONV/Data Entry. e. Enter 93 for CONV ID f. Enter 3 for CFIG ID. g. Click Info, to obtain information about the configuration. h. Enter 10.0 for GP Values. i. Enter , , , for MPIDs j. Click Apply. k. Click Cancel, to close the Template Entries form. l. Enter 913 for CONV ID. m. Enter 13 for CFIG ID. n. Click Info. o. Enter for GP Values. p. Enter , , , , for MPIDs. q. Click Apply r. Click Write File…(save as template.dat.apnd in the directory of your database) s. Click OK, Cancel, Close and Cancel. a d e f h i j g l m o p q n

WS11-18 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 11: Create template.dat.apnd File (Cont.) Use the Analysis: Build Template form to create the template.dat.apnd file containing the CONV definitions. a.Click Write File… b.Specify template.dat.apnd in the directory where the MSC.Patran database is. c.Click OK, Cancel, and Cancel. ac

WS11-19 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 12: Obtain a Copy of a mat.dat.apnd File In a DOS window, set to the directory which contains the MSC.Patran database, use get_qtran to copy the existing material property file mat.dat.apnd for exercise/sample problem prob4. The commands are given as follows: a. (DOS window) C:\Training\PAT312\Ws11> get_qtran If the message command not found is returned, this error indicates that there is not a path to p3.home. b.Enter prob4, (DOS window) C:\Training\PAT312\Ws11> prob4 c.Enter file name mat.dat.apnd, (DOS window) C:\Training\PAT312\Ws11> mat.dat.apnd d.There should be the file mat.dat.apnd in the database directory. Note: a mat.dat.apnd should now reside in the directory where the database is. This file contains more material properties than required. This will not adversely affect the analysis. Feel free to review the format and syntax of the mat.dat.apnd file. This file can be used as a boiler plate for creating other material property data files.

WS11-20 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation As an alternative to using get_qtran, the file mat.dat.apnd can be obtained manually. The steps are given as follows. a. Find the installation directory for MSC.Patran/2004r2. b. Click on the file folder named p3thermal_files. c. Click on the file folder named examples. d. Open file folder named qtran. e. Open file folder named prob4. f. Copy.apnd file mat.dat.apnd. g. Paste mat.dat.apnd file into the same directory as the exercise database. a f Step 12: Obtain a Copy of a mat.dat.apnd File (Cont.)

WS11-21 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 13: Prepare and Run Analysis Prepare and submit the model for analysis. a. Analysis. b. Analyze/Full Model/ Full Run. c. Click on Translation Parameters… d. OK. e. Click Solution Parameters… f. Click Run Control Parameters… g. Enter for Initial Temperature. h. Click Kelvin for Initial Temperature Scale. i. OK. j. OK. a c e f g h i b

WS11-22 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Continue to prepare and submit the model for analysis. a. Click on Output Request… b. Select Kelvin for the Units Scale for output Temperatures. c. Click on Nodal Results File Format… d. Under Select Thermal Entries to Output select first 8 items listed. e. OK. f. Click Diagnostic Output and select Convection Resistors. g. OK. h. OK. i. Apply. a b c f i h d e Step 13: Prepare and Run Analysis (Cont.)

WS11-23 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 14: Read and Plot Results Read and Plot the results. a. Analysis. b. Read Result/Result Entities. c. Click on Select Results File… d. Find the path that leads to exercise_11. e. Select nr000.nrf.01 for File name. f. OK. g. Click Select Rslt Template File… h. Select pthermal_nod_T.res_ tmpl. i. OK. j. Apply. k. If a warning appears click OK to close it. l. Reduce the node size by using the Node size icon. a b c g h i l j d f e

WS11-24 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 14: Read and Plot Results (Cont.) Plot the Results. a. Results. b. Create/Quick Plot. c. Select Time: D+ 00S… for Select Result Cases. d. Select Temperature for Select Fringe Result. e. Select the Fringe Attributes icon. f. Under Display select Element Edges. g. Click on Label Style… h. Select Fixed for Label Format. i. Using the slider bar select 4 for Significant figures. j. OK. k. Apply. a f g k i j h b e

WS11-25 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 14: Read and Plot Results (Cont.) Plot the value of the heat transfer coefficient. a. Select the Select Result icon. b. Select Time: D+ 00S… c. Select Average Convection Coefficient, (h) for Select Fringe Result. d. Click Apply. e. To view detailed convection resistor data look in the file qout.dat.01 file in Job Name subdirectory. Search for string CONVECTIVE RESISTOR DATA. a b c d Note: the nodal averaged values of h are displayed in the viewport.

WS11-26 PAT312, Workshop 11, December 2006 Copyright 2007 MSC.Software Corporation Step 15: Quit MSC.Patran Quit MSC.Patran. a. Select File. b. Click Quit from the drop down menu.