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.