Hi Fillia,
Thank you very much for your help! I have increase the fineness of the mesh but the result is not improving. I have tried to solve the problem with a more simple geometry that consists in a cube with a thin layer on top. I have increased the fineness to 9 and I have also refined the top layer of the model, but results in heat flow are not constant in the surface. I think that the problem is the thin layer on the top of my model, and I guess I am not improving the mesh properly. Do you have any advice to improve the mesh efficiently?
Isa