A composite plane wall consists of a 9 inch thick layer of brick and a 4 inch thick layer of insulation. The outer surface temperatures of the brick and insulation are 1260oR and 560oR, respectively, and there is perfect contact at the interface between the brick and the insulation. At steady-state, determine the heat conduction flux through the wall in Btu/h-ft2 and the temperature in oR at the interface between the brick and the insulation.
Brick Insulation
Data : k 1.4 0.05 Btu/h-ft2-oR
2 comments:
Why is the flux negative? Heat is going into AND out of the wall, so what's defined as positive flux?
George:
I got a negative heat flux because of the fact that I defined that x-axis so that it increases in the direction opposite to the flow of heat. It is ok if you get a positive heat flux. It just means that heat is flowing in the positive x-direction.
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