How Does Fourier's Law Apply to Heat Flow Through a Composite Wall?

Jay K
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Using Fourier’s law and an electrical analogy, derive the expression given below for the heat flow, Q, through a flat composite wall of surface area, A, with three layers of thicknesses x1, x2 and x3 and thermal conductivities k1, k2 and k3, and an overall temperature difference ΔT. State any assumptions.
 

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Welcome to PF!

Hi Jay! Welcome to PF! :smile:
Jay K said:
Using Fourier’s law and an electrical analogy …

What do you think the electrical analogy is? :wink:

(and what is Fourier's law?)
 

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