The boundary conditions are relatively easily implemented. At the cold boundary we specify the mass flux fractions and the temperature, that is, we solve

(13–22)

and

(13–23)

where is the inlet reactant fraction of the k th species and is the specified burner temperature. At the hot boundary we specify that all gradients vanish, that is,

(13–24)

and

(13–25)

The boundary conditions for depend on whether the given problem is a burner-stabilized or a freely propagating flame. The boundary conditions for each case are discussed in Boundary Conditions .