# Thermodynamics question: temperature between layers

1. Apr 11, 2017

1. The problem statement, all variables and given/known data

2. Relevant equations
h = k/d
1/h (total) = 1/h + 1/h + 1/h... + 1/h (surf)
Q/t = h A T

3. The attempt at a solution
For the thermodynamic one i got up to calculating the total heat transfer coeffecient but i dont know where to go from there as its asking for the outside temperature of the feathers, whilst giving an air temperature (-15 degrees).

Help would be greatly appreciated ~ Adam

2. Apr 11, 2017

### CWatters

Could you sketch the thermal "circuit" showing the temperature points and thermal resistance between each? Think ratios or "potential divider" if familiar with electronics.

3. Apr 11, 2017

Hello i tried sketching the circuit but i just cant seem to get it. Is there some sort of 3rd layer between the feathers and air? If so how would i go about finding the temperature of it? Also im not familiar with potential dividers

4. Apr 11, 2017

### CWatters

Look up "surface heat transfer coefficient". The "third layer" as you called it is the surface of the feathers.

Last edited: Apr 11, 2017