Conduction Flashcards
1
Q
When presuming steady state condition how do you calculate heat transfer via conduction
A
- imagine system is a circuit, V = IR
- V being change in temperature
- R being thermal resistance (dimensions + K)
- I being heat tranfer
- add R’s like in normal circuits
2
Q
Thermal resistance for walls
A
R = Δx / KA
3
Q
Thermal resistance for tubes
A
R = ln(R2 - R1) / 2πKL
4
Q
How is heat tranfer calculated for irregular shapes
A
Q = - KS(T2 - T1)
- shape factor (S), is only obtained through experimental analsys
5
Q
Thermal resistance for sphere
A
(1/r2 - 1/r1) / 4πK
