The model for premixed or partially premixed combustion can be split into two independent parts:
Model for the progress of the global reaction: Burning Velocity Model (BVM), also called Turbulent Flame Closure (TFC)
Model for the composition of the reacted and non-reacted fractions of the fluid: Laminar Flamelet with PDF
The mass fractions in the non-reacted fraction of the fluid, 
,
are obtained by linear blending of fuel and oxidizer compositions.
The species mass fractions in the burned fraction of the fluid, 
,
are computed by applying the Flamelet model.