I have modeled a furnace in the Gambit. I am getting a converged solution in the laminar and turbulant Flow. But when i give species transport along with the energy the at the first iteration message comes that Divergence dectected in the AMG solver : temperature.Please help me to solve this problem. thank you.

Hi, Try to play a little with Under-Relaxation Factors in Solve->Controls->Solution. The problem probably is with the rapid changes in temperature so the energy equation should have smaller factors. If doesn't work try to do the same with the species facotrs. You can also solve a "cold" flow first simply not solving the energy equation and if you get a cold solution then turn on again the energy equation. To turn off solving of one equation simply unselect required equation under Equations in Solve->Controls->Solution. Good luck.

Thanks i am using light diesel as a fuel. u said that cold flow. I think this means not enable the energy but only specie transport.I doing relaxtation factor reduce but slowly this going towards divergance. I am not soure that divergance come but the temperature in cell domain slowly increasing. by mansi

Solving supersonic mixing with 10 species and 12 reactions this workes for me: 1. Disabling species transport and energy. 2. once converged enabling species 3. Finally, once converged enabling energy I didn't reduce the relaxation factors but it may help as the initial factors in Fluent are pretty high.