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Thermal FEA Results Summary Steady State

Cold Shield T min = 69 K T max = 105 K. Cold Mass T min = 67 K T max = 73 K. Thermal FEA Results Summary Steady State. Thermal FEA Model Summary. System modeled using I-DEAS I8m1 TMG analysis software Thermal Transfer Mechanisms Modeled

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Thermal FEA Results Summary Steady State

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  1. Cold Shield T min = 69 K T max = 105 K Cold Mass T min = 67 K T max = 73 K Thermal FEA Results SummarySteady State

  2. Thermal FEA Model Summary • System modeled using I-DEAS I8m1 TMG analysis software • Thermal Transfer Mechanisms Modeled • Conduction between cold mass and vacuum jacket via (4) cold mass supports • Conduction between cold shield and vacuum jacket via (4) cold shield supports • Radiation between vacuum jacket and cold shield • Radiation between cold shield and cold mass • Vacuum Jacket fixed at constant 0 C • Conduction paths between vacuum jacket and cold structures modeled using numericalthermal couplings with constant conductances • Cold straps modeled using numerical thermal couplings with constant conductances • Shield cooler specified at T = 60 K • Cold mass cooler specified at T = 40 K

  3. Cold Mass Mass = 50 kg Surface Area = 1500 in2 Linear solid + thin shell element mesh Material: 6061 Al Conductivity: 150 W/m-C Emissivity: 0.05 Specific Heat: 850 J/kg-C Surface elements coating solid mesh Material: null Conductivity: 0 Thickness: 0 Specific Heat: 0 Cold Shield Surface Area = 4500 in2 Linear thin shell element mesh Thickness: 3.175 mm (0.125 in) Material: 6061 Al Conductivity: 150 W/m-C Emissivity: 0.05 Specific Heat: 850 J/kg-C Thermal FEA Model

  4. Cold Strap Thermal CouplingsConductance: G = k*A/LMaterial: copperk = 500 W/m-C Cold Shield Strap Cooler end of strap: T = 60 K Strap Width = 2 inch Leaf thickness = 0.005 inch Number leaves = 70 Length = 3 inch A/L = 0.006 m G = 3 W/C Cold Mass Strap Cooler end of strap: T = 40 K Strap width = 2 inch Leaf thickness = 0.005 inch Number leaves = 50 Length: L = 6 inch A/L = 0.002 m G = 1 W/C

  5. Cold Mass Supports Material: G-10 Conductivity: k = 0.5 W/m-C Length: L = 0.322 m (12.7 in) Area: A = 0.807 m^2 (1.25 in^2) Conductance per truss leg: - G = k*A/L - G = 1.25 E-3 W/C Conductance per truss ( 2 parallel legs): - G = 2.5 E-3 W/C Cold Shield Supports Material: G-10 + stainless steel Conductivity: kG10. = 0.5 W/m-C Conductivity: kS.S. = 15 W/m-C Length: LG10 = 0.0762 m (3 in) Length: LG10 = 0.0762 m (3 in) Area: As.s.. = 0.644 E-6 m^2 Area: AG10.. = 0.161 E-6 E-6 m^2 Conductance: G = k*A/L GG10 = 1.06 E-3 W/C GS.S. = 0.38 E-3 W/C Conductance per truss (G10 and SS in series): G = 0.001 W/C Insulating Supports( Thermal couplings between elements numerically defined in FE model)

  6. Thermal FEA Model Summary Listing of Steady State Analysis Parameters: Iteration Limit = 10000 Relaxation Factor = 1.0 Maximum delta T less than 0.001 Use loads at specified time 0.0 Listing of Solution Methods: Solution Method: Conjugate Gradient Iteration Limit = 100 Convergence Criterion = 0.000000010 Preconditionning Matrix Fill value = 10 Conduction Method: Element CG Convergence Trace OFF Listing of Radiation control: Calculation method: Oppenheim Residual View Factors method: Weighted Distribution Global Element Subdivision Parameter = 4 Space Enclosure OFF Advanced Parameters: Stefan-Boltzmann constant = 5.6696E-08 W/(m^2-K^4) Minimum View Factor to process = 0.0 Number of Axisymmetric Segments = 8 Listing of Reverse Sides 1 - COLD SHIELD Elements Source: Group 27 - ELEMENTS - COLD SHIELD Elements : 1557 Labels : 59621-61177 Create as separate elements OFF Element Label increment : 10000 IR Properties - Same as Front Side Solar Properties - Same as Front Side Thermal Couplings: COLD BLOCK STRAP: G = 1 W/C RED DETECTOR MOUNT: Join BLUE DETECTOR MOUNT: Join MECH BOX MOUNT : Join COLD TRUSS –Z: G = 0.0023 W/C COLD TRUSS +Z: G = 0.0023 W/C COLD TRUSS –X: G = 0.0023 W/C COLD TRUSS +X: G = 0.0023 W/C SHIELD TRUSS 1 : G = 0.001 W/C SHIELD TRUSS 2 : G = 0.001 W/C SHIELD TRUSS 3 : G = 0.001 W/C SHIELD TRUSS 4 : G = 0.001 W/C SHIELD COLD STRAP: G = 3 W/C Temperature B.C. VJ TEMP: 0 C COLD MASS COOLER TEMP -233.0 C SHIELD COOLER TEMP -213.0 C Heat Load B.C. STRAY HEAT LOAD: 5 W Initial Temperature LN CAN TEMP: -193 C Radiation Request VJ TO COLD SHIELD COLD SHIELD TO COLD MASS

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