WORKSHOP 16 A CONCENTRIC TUBE, COUNTERFLOW HEAT EXCHANGER

WS16-2 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation

WS16-3 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Model Description In this exercise you will create a simple 3D model representing the entry region of a concentric tube, counterflow heat exchanger. Owing to symmetry considerations, only one-fourth of the heat exchanger configuration needs to be modeled. A team of university students is considering a makeshift heat exchanger, to cool and discard gaseous coolant from a small reactor. The heat exchanger is designed to begin at the reactor coolant plenum. In the event of an emergency, a safety valve would open to draw the coolant from the plenum into the exchanger (a process which will require approximately 60 seconds to complete). A secondary liquid coolant would then be used to decrease the temperature of the reactor coolant, before the reactor coolant enters a complex filtration process. The existing reactor coolant system is comprised of steel. The material proposed to contain the secondary coolant flow is simple lead. At the junction between the plenum and the heat exchanger, the gaseous fluid would exhibit a high mass flow rate at 350°C. The entry length variation of the convection coefficient between the steel and the gas is expected to follow: h= *z 3 W/m 2 K (where z is the distance from the plenum). The liquid coolant will flow between the steel coolant tube and the lead housing, will be fully developed and is expected to exhibit a high convection coefficient (3000 W/m 2 K ). The students prime concern with the design is the determination of the maximum temperature that the lead tube will exhibit after 60 sec of use.

WS16-4 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Objectives Demonstrate MSC.Thermal capabilities for gap convection problems. Practice basic modeling skills using MSC.Patran.

WS16-5 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Exercise Overview 1. Create a new database named exercise_16.db. 2. Use the Create and Edit actions on the Geometry form to construct a 2D representation of the heat exchanger. 3. Mesh the 2D geometry created in the previous step and use Sweep/Element/Extrude to develop the 3D FEM model. 4. Create 4 nodes to represent the spatial variation of the convection coefficient of the reactor coolant over the entry length. 5. Apply the appropriate Element Properties to the FEM model: Quad4s – Steel MID 353; Hex8s – Lead MID Create/Spatial/Field, PCL Function to define the variation of the convection coefficient of the reactor coolant flow in the stream wise direction. 7. Apply a fixed temperature of 350°C to the nodes representing gaseous coolant. 8. Create 2 Fixed Coefficient Convection Boundary Conditions. 9. Perform a Transient Analysis for 60s assuming a global initial temp of 25°C. 10. Prepare and submit the model for analysis. 11. Read results file and plot results. 12. Quit MSC.Patran.

WS16-6 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 1: Create a New Database Create a new database called exercise_16.db. a. File / New. b. Enter exercise_16 as the file name. c. Click OK. d. Select Based on Model Tolerance. e. Enter 0.07 for Approximate Maximum Model Dimension. f. Select MSC.Patran Thermal as Analysis Code. g. Select Thermal as Analysis Type. h. Click OK. a b c d e f g h

WS16-7 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 2: Create 2D Heat Exchanger Construct a 2D representation of the heat Exchanger. a. Geometry. b. Create/Curve/2D ArcAngles. c. Enter 0.05 for Radius. d. Enter 180 for Starting Angle. e. Enter 270 for End Angle. f. Apply. g. Enter 0.06 for Radius. h. Apply. i. Create/Surface/XYZ. j. Enter for Vector Coordinates List. k. Apply. a b c d e f i j k

WS16-8 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 2. Geometry: Create / Curve / XYZ Construct a 2D representation of the heat Exchanger. a. Turn on Labels using the following icon. b. Edit/Surface/Break. c. Select Curve for Option. d. Enter Surface 1 for Surface List. e. Enter Curve 2 for Break Curve List. f. Apply. g. When the message appears, click Yes. h. Delete/Any. i. Select Surface 3 for Geometric Entity List. j. Apply. k. Refresh by selecting the following icon. a b c d e f k

WS16-9 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 3: Mesh the Surfaces Mesh the surface with quad4 elements. a. Finite Elements. b. Create/Mesh/Surface. c. Enter for Global Edge Length. d. Select Paver Mesher. e. Select Surface 2 for Surface List. f. Apply. g. Create/Mesh/Curve. h. Enter for Global Edge Length. i. Select Curve 1 for Curve List. j. Apply. a b c d e f g h i j

WS16-10 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 3: Mesh the Surfaces Mesh the surface with quad4 elements a. Finite Elements. b. Sweep/Element/Extrude. c. Click on Mesh Control… d. Enter 20 for Number. e. OK. f. Enter 0.2 for Extrude Distance. g. Select Delete Original Elements. h. Type in Elm 1:# for Base Entity List. i. Apply. a b c d e f g h i

WS16-11 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 4: Create Ambient Nodes Use the Tool Bar to change the view. a. Hide Labels. b. Iso 1 View. c. Node Size. d. Fit View. d bac

WS16-12 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 4: Create Ambient Nodes Create 4 nodes to effect a spatial variation of the convection coefficient magnitude to represent a developing flow. a. Finite Elements. b. Create/Node/Edit. c. Enter 9996 for Node ID List. d. Deselect Associate with Geometry(for all nodes). e. Enter [0 0 0]. f. Apply. g. Enter 9997 for Node ID List. h. Enter [ ] for Node Location List. i. Apply. j. Enter 9998 for Node ID List. k. Enter [ ] for Node Location List. l. Apply. m. Enter 9999 for Node ID List. n. Enter [ ] for Node Location List. o. Apply. p. Rotate the display to verify the new nodes using Iso 2 view. q. Revert the display back to front view. a b c d e f q p

WS16-13 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 5: Apply Element Properties Create two element properties, one for the shell elements, and the other for the solid elements. Use the MID for the material. a. Properties. b. Create/2D/Shell. c. Enter Steel for Property Set Name. d. Click Input Properties… e. Enter 353 for Material Name. f. Enter for Shell Corner Thickness. g. OK. h. Under Select Members select all the Quad elements, Elm 1141:1400. i. Add. j. Apply. a b c d e f g h i

WS16-14 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 5: Apply Element Properties Perform the same steps for the outer lead portion. a. Properties. b. Create/3D/Thermal 3D Solid. c. Enter Lead for Property Set Name. d. Click Input Properties… e. Enter 21 for Material Name. f. OK. g. Under Select Members select all the solid elements, Elm 1:1140. h. Add. i. Apply. a e f b c d g h

WS16-15 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 6: Create Spatial Field Create a function to define the variation of the convection coefficient of the reactor coolant flow in the stream direction. a. Fields. b. Create/Spatial/PCL Function. c. Enter convection _f_of_z for Field Name. d. Enter 200-(13000*Z*Z*Z) for Scalar Function. e. Apply. f. Under Action: change to Show. g. Select convection_f_of_z for Select Field To Show. h. Click Specify Range… i. Enter 0.2 for Maximum. j. Enter 10 for No. of Points. k. OK. l. Apply. m. Cancel. n. Unpost Current XYWindow. a b c d f g h i j k n

WS16-16 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 7: Apply Boundary Conditions Apply a fixed temperature of 350°C to the nodes representing gaseous coolant. a. Loads/BCs. b. Create/Temperature/Nodal c. Select Fixed for Option. d. Enter interior_flow for New Set Name. e. Click Input Data… f. Enter for Fixed Temperature. g. OK. h. Click Select Application Region. i. Select FEM Geometry Filter. j. Click in Select Nodes box and select Node 9996 to k. Add. l. OK. m. Apply. a b c d e f g h i j l m k

WS16-17 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 8: Create 2 Fixed Coefficient Conditions Create a between regions convection BC. a. Select Loads/BCs. b. Create/Convection/Element Uniform. c. Select Fixed Coefficient for Option. d. Enter inner_flow for New Set Name. e. Select 2D for Target Element Type. f. Select Nodal for Region 2. g. Click Input Data… h. Click Select Spatial Field… i. Select convection_f_of_z in the Spatial Field box. j. Click OK. k. Click Select Application Region… b c d e f g h j k a

WS16-18 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Create a between regions convection BC. (continued) a. Select FEM Filter. b. Click in Application Region/Select 2D Elements or Edges input box. c. Select all the Quad elements, Elm 1141:1400. d. Add. e. Click in Coupling Region/Select Nodes input box. f. Select the nodes in the upper right corner of the display, Node 9996:9999. g. Click Add, OK, and Apply. h. Select Preferences. i. Select Picking. j. Select Enclose entire entity for Rectangle/Polygon Picking. k. Click Close. Step 8: Create 2 Fixed Coefficient Conditions a b e d g g j

WS16-19 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 8: Create 2 Fixed Coefficient Conditions Create a between regions convection BC. (continued) a. Select Loads/BCs. b. Create/Convection/Element Uniform. c. Select Fixed Coefficient for Option. d. Enter outer_flow for New Set Name. e. Select 3D for Target Element Type. f. Select 2D for Region 2. g. Click Input Data… h. Enter 3000 for Convection Coefficient. i. OK. j. Click Select Application Region… h i a b c d e f g j

WS16-20 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 8: Create 2 Fixed Coefficient Conditions Create a between regions convection BC. (continued) a. Select FEM Filter. b. Click in the Application Region/Select 3D Element Faces input box. c. Using the Ctrl key and the left mouse button define a polygon selecting only those lead elements which contact the outer fluid flow. d. Add. e. Click in Coupling Region/Select 2D Elements or Edges input box. f. Select all the Quad elements, Elm 1141:1400. g. Add. h. OK. i. Apply. a b d e g h

WS16-21 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 8: Create 2 Fixed Coefficient Conditions

WS16-22 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 9: Transient Analysis Prepare and submit the model for analysis. a. Analysis. b. Analyze/Full Model/Full Run. c. Click Solution Type… d. Select 1, Transient Run for Select Thermal Solution. e. OK. f. Click Solution Parameters… g. Select Celsius for Calculation Temperature Scale. h. Click Run Control Parameters… i. Enter 60 for Stop Time. j. Enter 25.0 for Initial Temperature. k. OK. l. OK. a b d g h k c f

WS16-23 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 10: Prepare and Run Analysis Prepare and submit the model for analysis. (continued) a. Click on Output Request… b. Select Celsius for Units Scale for Output Temperatures. c. Click Print Interval Controls… d. Enter 20.0 for Initial Print Interval. e. OK. f. OK. g. Apply. a b c d e f g

WS16-24 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 10: Prepare and Run Analysis When the Heartbeat returns to green open a command prompt or UNIX shell to monitor the progress of your job. Recall that the tools for monitoring a job are as follows: a. cd - to change to the Job Name subdirectory. b. tail -f patq.msg.01 - to monitor the generation of the input file (UNIX only). c. qstat l – to link the status file from each time step together. d. qstat c - to monitor the solver progress.

WS16-25 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 11: Read and Plot Results Read and plot the results. a. Analysis. b. Read Result/Result Entities. c. Click Select Results File… d. Under directories find the path that leads to exercise_16. e. Select the file nr2.nrf.01. f. Click OK. g. Click Select Rslt Template File… h. Select pthermal_1_nodal. res._tmpl. i. OK. j. Apply. a b c d f g h i j e

WS16-26 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 11: Read and Plot Results Change the display. a. Change to Iso 1 View. b. Reduce the Node Size. c. Reset graphics. d. Fit View. a b c d

WS16-27 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 11: Read and Plot Results Read and plot the results. a. Results. b. Create/Quick Plot. c. Select Time: D+ 01 S…for Select Result Cases. d. Select Temperature for Select Fringe Result. e. Select the Fringe Attributes icon. f. Select Element Edges for Display. g. Click Label Style. h. Select Fixed for Label Format. i. Use the slider bar to select 4 for Significant figures. j. OK. k. Apply. a h i j b f g k

WS16-28 PAT312, Workshop 16, December 2006 Copyright 2007 MSC.Software Corporation Step 12: Read and Plot Results Quit MSC.Patran. a. Select File. b. Click Quit from the drop down menu.