Overall Thermal Conductivity of Three different layers

[Izazo]

TL;DR

How to calculate the overall conductivity of three layers bonded with each other having different thermal conductivities?

Overall thermal conductivity?
for example, there are 3 layers made of different materials, having different thermal conductivities bonded with each other;
conductivity of layer 1= k_1 = 1 W/m-K
thickness of layer 1= t_1 = 0.004 m

conductivity of layer 2= k_2 = 148 W/m-K
thickness of layer 2= t_2 = 0.0003 m

conductivity of layer 3= k_3 = 0.23 W/m-K
thickness of layer 3= t_3 = 0.004 m

 

[trurle]

You should calculate thermal resistance of each layer, sum up resistances end recalculate compound conductivity from the sum.