SW is not for you. Combustion involves a chemical reaction - something SW cannot handle. Heat is generated and the properties of the gas change. The oxidation of the fuel takes place on a two-dimensional plane separating the fuel from the oxidant. This front is in constant motion. It is a very complex problem.
I am a combustion engineer and I use SW CFD to study flows up to the flame (e.g., venturi mixers, burner ports, headers, etc) and downstream (flow, heat transfer through the heat exchanger, stack, etc.). SW is pretty good handling these items. You'll need to spend more money on something like ANSYS to really study the particulars of the combustion process.
If you are able to use linux, you can try openfoam.
I suggest that all of you who would like the ability to simulate combustion with Flow Sim, then please let us know by filing an enhancement request. This is definitely one functionality that I think we can help you out with, and I'd like to see it myself too.
thanks all for all your suggestions.
Enhancement request already exists:
SPR 541437 - Support Combustion.
I voted for this enhancement request.
Just login to customer center, choose enhancement requests, then look for SPR 541437. You then click on the enhancement, fill in the fields, and finally and choose "Save details and vote for this enhancement".