Volumetric Source Term

Megan

I'm trying to run a simulation of wood burning in a furnace. I am only interested however in the stage of volatile combustion, therefore I have made a small volume around the 'crib wood' in the run and am using a volumetric source term to introduce the surrogate for wood volatiles as my fuel (formaldehyde - CH2O). I am using a non-premixed combustion model (pdf - mixture fraction). I'm just wondering if I need to specify more than a mass (kg/m3-s) and mixture fraction (kg/m3-s) source term. Should I also be specifying an energy, momentum, and mixture fraction variance source term? How should I determine these? Any help would be appreciated. Thanks so much.