[navneet]

Hi guys

I am solving partially premixed combustion and predictions of NOx for a domain with conjugate heat transfer. My domain consists of totally 3 burners of partially premixed type which burn inside 3 heat exchanger tubes. Initially I started with a simplified domain with a single burner and single tube. The results were exactly as expected. While solving the 3 burner configuration, I am facing problems with the combustion analysis.

As per the procedure I initially start with cold flow analysis with which I obtained correct results. I am using a PISO pressure-velocity method. After I switch on energy, pdf and progress variable, and provide a patch of 1300 K at the ignition point.

Combustion takes place only in a single tube, and in other tubes reverse flows develop and eventually combustion happens behind the burners which was pretty shocking. Different boundary conditions were tried, but the problem occurred in all cases when combustion was switched on. I am not able to understand the reason for this.

Please let me know if anyone has a solution for this.