If you are meshing flat parts, you can use a draft quality mesh option, which will reduce the number of degrees of the mesh
Where could I find the draft qualtiy mesh?
The sold model that I have is a 70 Ft tube lenght surrounding by a cover. The hot gas flow inside the tube and emit radiant heat to the floor. I have a heat source at the beginning of the tube with a fixed firing rate.. The goal to obtain net radiant heat on the floor.
Could you advise what is the best way to mesh "Automatic versus manual". Also how to obtain from the simulation the part of the heat lost as a convective heat