Laminar flame speeds of methane-air mixtures under reduced and elevated pressures

Using the counterflow methodology, the laminar flame speeds of methane-air mixtures have been accurately determined over the pressure range of 0.25-3 atm and over extensive lean-to-rich concentration ranges. These flame speeds are then compared with the numerically calculated values obtained by using various published kinetic schemes of either the C₁ mechanism or the full C₂ mechanism. Two such schemes show very close agreement with the experimental data. However, available information cannot further differentiate the relative superiority between them for flame speed calculations, especially the importance of C₂ reactions for moderately rich situations. Two reduced mechanisms are also deduced through sensitivity analysis and are expected to be useful for flame speed calculations and approximate flame structure studies.