# Radiation heat transfer (V-shaped and rect cavity)

1. Jul 24, 2006

### daviduta

Hello,
I need help with this problem,

Find radiosity B as a function of coordinates (x,y) over a V-shape or rectangular cavity. Consider the two walls and the surroundings to constitute an enclosure. Without any loss of generality, the cavity can have a unit depth. The temperature and emittance for the cavity walls have constant values. Calculate the effective emittance
{using equation, ε/ε a = Q/Qb = Q/(σAo(Tw^4 – Too^4)) } as a function of the local emittance for configurations selected from the following figures,

http://img162.imageshack.us/my.php?image=64dg5.jpg
http://img162.imageshack.us/my.php?image=66fi2.jpg

ε = Common emittance
ε a = Apparent emittance
Q = Effective emissive power of the cavity
Qb = Radiant emission of a black surface stretched across the opening of the black walled cavity
Ao = Area of fictitious surface stretched across cavity opening
Tw = Wall temperature
Too (Tinfinity) = External environment temperature
σ = Stefan Boltzmann’s constant