1. (60 pts) A plane wall is a composite of two materials, A and B. Material A is 0.5 cm thick and has a thermal

material A in contact with the insulated boundary needs to below 90 °C, so that the material A can be stable

is applied to material A such that 15 W/cm is generated as heat. The surface temperature T, of the

conductivity of k, = 20 W/(mK). The back side of material A is thermally insulated. Electrical current

and do not melt. Material B is 0,3 cm thick and has a thermal conductivity of k, = 30 W/(mK). The

surface of solid B is exposed to air. The surface temperature, 7,, of material B is 70 °C. The bulk air

a) Use shell balance to derive the following temperature profile of material A. The process is at steady

temperature, T, is constant at 25 °C.

state.

T=-

-x² + ₂x + G₂

b) Determine the constants G₁ and C₂. Clearly show the boundary conditions used.

c) What is the heat flux? Unit must be in SI unit.

e)

d) Determine the temperature T, (unit in °C) at the interface of materials A and B.

of the flowing a

Determine the temperature T, (unit in °C) at x = 0 of the insulated surface.

Q™

2KA