I have been facing problem with net heat balance. I am able to get the solution in terms of residuals coming down upto the order of 1e-4. Also i am monitaring temperatures on few surfaces, and these are also getting constant for this solution. But the net heat flux is not coming down to zero. The total heat input inside the domain is around 80 Watts. Net heat flux is coming around 33W. Has anyone faced this type of situation. Please help in this regard..Thanks in advance Trilok

You need to converge the energy residual to at least 1e-06. And I would advise a second order solution, especially if you are using an unstructured grid.

Do a first order solution first and then change to a second order solution. Use the under-relaxation factors if you are having difficulty converging the energy, but do not relax anymore than 0.9.

Thanks Eric, Thanks for your response. In fact for energy i am converging it to 1e-6. I have also tried the second order solution and there is no improvement in net heat flux.

Hi, First you check whether you have any shadow-walls in your problem. If so, while calculating net heat transfer you deselect them. And find heat transfer.