S6-1 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation SECTION 6 RADIATION

S6-2 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS n 1x1x0.1 plate n k x =204.0 Btu/hr/(ft*R) for aluminum n FE model using 1 plate element (CQUAD4) n Applied heat flux of Btu/hr/ft 2 for 3 surface orientations (0.0 and 60.0 degrees) n Radiation to surroundings at 0.0 degrees Fahrenheit n Run SS analyses to determine equilibrium temperatures n Post process n Examine.f06 acsii results file n Problem based on MSC.Nastran Thermal Analysis Users Guide, Example 4b

S6-3 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS n Objective: modeling directional solar heat flux loads, and the plate is at radiative equilibrium n Note: the picture on the left displays the directional heat load in the - Y direction.

S6-4 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS n Note: the surface lies in the X-Z Plane, and the mesh density(one shell element) corresponds to Global Edge Length equal to 1.0

S6-5 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS n Create thermal properties for solid material aluminum

S6-6 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS n Create element properties for the single shell element u Material: alum u Thickness = 0.1

S6-7 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS n Create radiation LBC for radiation to ambient temperature u Emissivity = 1.0 u Absorptivity = 1.0 u Ambient temperature = 0.0 F u View factor = 1.0 u AR: Surface 1; has associated single shell element

S6-8 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS n Create LBC applied heat with specified direction u Absorptivity = 1.0 u Heat flux = Btu/hr/ft**2 u Vector = u AR: Surface 1

S6-9 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS n Run analysis Analysis: Analyze/Entire Model/ Full Run n Solution Type… u Steady State u Solution Parameters… l Radiation Parameters…

S6-10 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS n Flux direction is zero degrees from normal to plate; flux direction vector is. n The temperature is constant at 282 F. This result agrees with that for Example 4b in the MSC.NastranThermal Analysis Users Guide. Angle is 0 degree from normal

S6-11 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS n It is seen that the temperature is F. n The output from each CHBDYG element reflect the direction heat load of 442 Btu/hr and the emitted radiation to space at zero degree F 0 0 SUBCASE 1 LOAD STEP = E+00 T E M P E R A T U R E V E C T O R POINT ID. TYPE ID VALUE ID+1 VALUE ID+2 VALUE ID+3 VALUE ID+4 VALUE ID+5 VALUE 1 S E E E E MSC/NASTRAN JOB CREATED ON 08-JUL-98 AT 10:04:05 JULY 8, 1998 MSC/NASTRAN 12/11/96 PAGE 10 DEFAULT 0 SUBCASE 1 LOAD STEP = E+00 H E A T F L O W I N T O H B D Y E L E M E N T S (CHBDY) ELEMENT-ID APPLIED-LOAD FREE-CONVECTION FORCED-CONVECTION RADIATION TOTAL E E E E E-03 SUBCASE 1 Extract from MSC.Nastran ASCII Results File

S6-12 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS PSHELL CQUAD MAT $ Nodes of the Entire Model GRID GRID GRID GRID $ Loads for Load Case : Default $ Fixed Temperatures of Load Set : radbc SPC $ Directional Heat Flux of Load Set : qvect QVECT B + B 1 $ Radiation Boundary Conditions of Load Set : radbc RADBC $ Initial Temperatures from Temperature Load Sets TEMP $ Default Initial Temperature TEMPD $ CHBDYG Surface Elements CHBDYG 1 AREA4 1 + C + C $ Radiation Material Properties RADM $ Scalar Points SPOINT 5 $ Referenced Coordinate Frames ENDDATA Extracted from MSC.Nastran model.DAT file

S6-13 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS QVECT, SID, Q0, TSOUR,CE,E1, E2, E3, CNTRLND,+,EID1,EID2 QVECT,2,442.,,,0.,-1.,0.,,+ +,1 Extracted from MSC.Nastran model.DAT file n QVECT specification in bulk data

S6-14 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 7 DIRECTIONAL HEAT LOADS n Change the angle from zero degrees from normal(vector ) to 60 degrees from normal. n The direction cosines for 60 degrees is ( ,-0.5,0.0) for (E1,E2,E3) n Can then modify the QVECT bulk data entry n QVECT,2,442.,,, ,- 0.5,0.

S6-15 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation n Perform Workshop 12 Radiation to space in the exercise workbook n Perform Workshop 13 Directional Heat Loads in the exercise workbook. EXERCISES

S6-16 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n Three 1x1x0.1m plates are disposed along the basic X-axis at 1m intervals, another plate is off to one side. u Each plate is represented by one CQUAD4 element n The left-most plate is held at degs K,and the ambient space temperature is at 0 deg K n The material for all CQUAD4s is aluminum (k = W/m/K) n Perform a SS analysis to determine the equilibrium temperatures of the plates n Review the.DAT,.F06, and.PCH files n Based on Exercise 5a in the MSC.Nastran Thermal Analysis Users Guide

S6-17 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n Create first surface. It is in the YZ plane. n Copy the first surface created two times by transforming it using the vector. n Create the final surface, Surface 4, parallel to the XY plane.

S6-18 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n Display the normal for the surfaces. n The normal for Surface 1:3 is in the positive X-direction. n The normal for Surface 4 is in the positive Z-direction.

S6-19 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n Change the direction of the normal for the surface at the right of the surfaces, Surface 3.

S6-20 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n IsoMesh all surfaces with one CQUAD4 element per surface. u Surface List: Surface 1:4 u GEL: 1.0

S6-21 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n Create isotropic material properties for the solid plates. u Aluminum u K = Watts/m/K

S6-22 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n Create 2D shell element properties u Aluminum u Thickness = 0.1 m u AR: Surface 1:4

S6-23 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n Apply constant temperature to left plate, Surface 1. u 2000 degrees K u AR: Surface 1

S6-24 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n Create radiation LBC using an enclosure u Surface option: Top u Surface can be shaded, yes u Enclosure ID: 10 u End surfaces, Surface 1,3,4

S6-25 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n Create another radiation LBC using an enclosure u Surface option: Top u Surface can shade, yes u Enclosure ID: 10 u Middle surface, Surface 2

S6-26 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n Create another radiation LBC using an enclosure u Surface option: Bottom u Surface can shade, yes u Enclosure ID: 10 u Middle surface, Surface 2

S6-27 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n Run analysis Analysis: Analyze/Entire Model/ Full Run n Solution Type… u Steady State u Solution Parameters… l Radiation Parameters…

S6-28 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION n The hottest plate is at the left at 2000 degrees K. The coldest plate is at the right at 773 degrees K.

S6-29 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION $ Radiation Enclosures of Load Set : top RADCAV VIEW3D* * B * B VIEW 1 10 KBSHD $ Radiation Enclosures of Load Set : middle_top VIEW 2 10 KSHD $ Radiation Enclosures of Load Set : middle_bottom VIEW 3 10 KSHD RADSET 10 Extracted from MSC.Nastran model.DAT file

S6-30 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation CHBDYG 1 AREA C + C CHBDYG 2 AREA D + D CHBDYG 3 AREA E + E CHBDYG 4 AREA F + F $ Radiation Material Properties RADM 1 1. PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION Extracted from MSC.Nastran model.DAT file

S6-31 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION 0 *** VIEW FACTOR MODULE *** OUTPUT DATA *** CAVITY ID = 10 *** ELEMENT TO ELEMENT VIEW FACTORS C* PARTIAL SURF-I SURF-J AREA-I AI*FIJ FIJ ERROR SHADING ERROR SCALE E E E E-02 NO NO E E E E-02 NO NO E E E E-01 NO YES E E E+00 0/ E E E SUM OF E E E E E E-02 NO NO E E E E-01 NO YES E E E SUM OF E E E E E E-02 YES NO E E E E E E E-02 YES NO E E E SUM OF E E SUM OF E E SUM OF E E-01 Extract from MSC.Nastran ASCII Results File

S6-32 NAS104, Section 6, March 2004 Copyright 2004 MSC.Software Corporation PROJECT 8 SINGLE CAVITY ENCLOSURE RADIATION 0 SUBCASE 1 LOAD STEP = E+00 T E M P E R A T U R E V E C T O R POINT ID. TYPE ID VALUE ID+1 VALUE ID+2 VALUE ID+3 VALUE ID+4 VALUE ID+5 VALUE 1 S E E E E E E+03 7 S E E E E E E S E E E E+02 Extract from MSC.Nastran ASCII Results File