Propagation characteristics of a spherical premixed flame in a constant volume bomb after spark ignition were investigated by analyzing pressure histories and the time dependency of the flame radius was examined using methane-air and propane-air mixtures over a wide range of equivalence ratio from lean to rich. The dependency was interpreted in terms of the effects of positive flame stretch on the laminar burning velocity. In order to estimate the sensitivity of the laminar burning velocity to the flame stretch, which is characterized and described by Markstein number, the mass burning velocity was calculated by analyzing the pressure profiles. The results obtained were compared with those reported by many researchers. Comparison of the results for methane-air mixture with those for propane-air mixture exhibited contrastive behavior, being typical of the flame propagation of lighter and heavier hydrocarbon fuels.
