Radiation Modelling
 

Dear all,
I need to model an annulus where nitrogenum is flowing in laminar conditions. The thickness of annulus is 5mm, and the inner radius is 27mm. The two surfaces have two different temperature (600 outer and 400 inner).
I would like to simulate the radiative exchange too inside the annulus. Wich model do you think is better to set for a correct analysis?
Thanx

Which model for what physics?

This is a question which it will be best for you to answer yourself, then you know WHY the models you choose are best. Do the tutorials, read the documentation and try all the models (at least the ones which look relevant) and compare how they rate. They will all have advantages and disadvantages.