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Heat Transfer Simulation for the Welding of the T-Section
Boundary Conditions
• This model was run with a Gaussian heat flux distribution for the weld zone as used in other studies.
• The weld heat transfer model used is a combination of rapid heat flux followed with constant (melt) temperature imposed at the weld zone as verified by experiments.
Boundary Conditions (cont’d)
• The heat transfer coefficients on all surfaces were calculated using the vertical and horizontal plate correlations available in literature.
• Radiation boundary condition was applied where temperature was high.
MATERIAL K THERMAL
COND.W / m K
DENSITY
Kg / m3
CpSPECIFIC
HEATJ / Kg K
TYPE OF
SUB DOMAIN
Stainless SteelAISI 316
13.4 8238 468 T-section and outer can
Pure Copper 401 8933 385 Cladding and Conductors
Glass fine fiberOrganic bonded
0.036 105 795 Gap between can and copper
cladding
Kapton type 100 HN film
0.12 1.42 x 103 1.09 x 103 Ground or Outer Insulation
Kapton +Glass Layers
0.042 631 913 Inner Insulation over Copper Conductors
Properties TableAll Properties have been taken at 300 K
T- Section: Stainless Steel
Gap: Glass
Cladding: Pure Copper
Outer Insl: Kapton
Inner Insl: Kapton+Glass
Conductors: Pure Copper
All Dimensions are in inches.All temperatures are in Kelvin, except the graphical presentation of temperature with time where Celsius is used for easier comparison with other (experimental) results.
Gaussian heat flux imposed at the weld zone
0 < time < 0.01 secs
Addition of heat flux
Constant temperature imposed at the weld zone
0.01 < time < 1.5 secs
Constant Temperature
Constant Temperature
Constant Temperature
Constant Temperature
Natural Cooling with Convection and Radiation
1.5 < time < 60 secs
Natural Cooling
Natural Cooling
Natural Cooling
Natural Cooling
Natural Cooling
Natural Cooling
Natural Cooling
Natural Cooling
Natural Cooling
Natural Cooling
Next few slides show temperature
profile at these specific locations
1-2 Glass+Kapton
2-3 Kapton
3-4 Cu cladding
4-5 Glass
6 Highest temp point
during welding
0 10 20 30 40 50 60
0
100
200
300
400
500
600
700
800
Time in seconds
Tem
pera
ture
in C
Temperature at various Locations
1
2 3
4
5
Conclusions• The temperatures reached in this model are higher
than in the two test cases because the thickness of steel sheet used here is 0.04” compared to the 0.06” used earlier.
• The temperature results here (2D) are higher (at least by 15% based on experiments) when compared with a 3D model.
• The maximum temperature at the edge of glass insulation observed here is 750 °C. The lower estimate for the melting of fiberglass is 820 °C.