I built a nonpremixed combustion model using Fluent, but the temperaure is very high (2850K) which is not I expected.

And how to include the Buoyancy effect into the simulation?

Your suggestions are welcomed!

Thanks

If you're using a pdf model make sure it is non-adiabatic.

For buoyancy, click 'gravity' in the operating conditions panel and change z-parameter to -9.18 m/s2.

Thank you for your suggestion. But in the menu, non-precmixed combustion could be modeled either by "pdf" or "species transport". This time I will try "pdf"to see the effect.

Thanks!

If you used species transport, don't forget to include radiation to get rid of all that heat.