heat transfer

Question 1

Assumptions for a plane wall

Answer 1

Heat conduction is SS
* Heat conduction is 1D since the wall is large relative to the thickness and the thermal conduction on both sides are uniform (could also be if the shape is symmetrical about the centreline).
Thermal conductivity is constant
* There is no heat generation

Question 2

assumptions for layered wall

Answer 2

(1) One-dimensional conduction
(2) Steady-state conduction
(3) Constant properties
(4) Negligible contact resistance