Effects of the scalar dissipation rate on the steady laminar flamelet model

The effects of the scalar dissipation rate (SDR) on the quenching points of the steady laminar flamelet model at different stoichiometric ratios of reactants are investigated for a one-step reversible reaction with the Arrhenius rate. SDRs are either presumed uniform or modeled by the mapping closure approach. With these two models, steady flamelet equations are solved in mixture-fraction space, and complete 'S-shaped' curves are obtained. The results show that the SDR models affect the locus of the 'S-shaped' curves and the quenching points are remarkably different. The quenching state is reached at a lower χst for χ=χst but at a higher χst for χ=χstexp[-2 erfc-1(2z)2]. However, when the flame state is far from the quenching point, the difference in 'S-shaped' curves is small. This result is associated with the mixed state of the reactants; the poorer the mixing, the more remarkable the difference in 'S-shaped' curves becomes.