Hi all,

I am trying to model the tempertare field in a ventilated space using Fluent and am having difficulty with one of the boundary conditions. I have a heated plate in the middle of my room. If a I specify a constant temperature bc I get a solution that works, but isn't what I'm concerned with. If I specify a constant flux (say 1000W for a 1kW heater) I all of a sudden egt temperaturesin my domain of 5000K, which is obviously ridiculous. Even when I reduce the heat flux to less than 40 W (less than a light bulb) I still get ridiculous answers.

Has anyone else encountered this and if so what can I do?

Diogo

What are the boundary conditions you apply to the wall of the room. If u say all the walls are adiabatic, then the heat added by the hot plate just stays inside the room and the temperature keeps on increasing until infinity. Try to define a zone where you can apply a mass flow boundary or a constant pressure boundary.This will take care of the heat being carried away by advection.

No that's not the problem - I have a flow in at low level and out at a high level, which as you said i sprecisely supposed to carry the heat away, but it doesn't do that and temperature doesn't climb to infinity, but some unrealistically high level.

Thanks for the suggestion though

Have you compared the heat flux you are trying to apply with the FLUENT-computed heat flux when you apply the constant temperature condition? This might help steer you toward the source of the problem.