How to explicitly model a heat sink
 

Hi there

I'm trying to model a relatively simple problem but having some difficulties with how to reformulate it in "fluent terms". Let me put it as simple as possible:

Coolant flowing through circular tube. Both the tube and the coolant have a non-homogeneous internal heat generation (coming from X-Rays). Let's consider the tube adiabatic which means that coolant is releasing all the heat. What I would like to calculate is the radial temperature profile (to later calculate thermal stresses). Since I'm only interested in the radial profile there's no need to actually model the flow throughout the tube (in the axial dimension). We can assume that in the axial cut I want to calculate the T profile the flow is fully developed and that I know the convection coefficient. Is there a way to model this 2D problem with Fluent? Can you define a negative source term in the coolant cell so as to represent a heat sink? If so, and considering that I also have a non-homogeneous heat source in the same cell (from the X-rays) would it be licit to subtract to this non-homogeneous X-Rays heat source the total heat that has to be released (in this case evenly distributed through the fluid cell?). I hope I explained myself!

I would acknowledge any help you could provide me. Thanks in advance

Can someone help me here? Is it that the problem isn't clear? It basically boils down to the following question: Which is the easiest way to calculate the radial T profile on an adiabatic tube with internal heat generation.