In this study Lewis number (Le) for laminar premixed flame in oxy-hydrogen stoichiometric mixture was investigated numerically. This is the first time to analyze values of Le for the whole flow field. It is known from definition that low Le is beneficial in flame propagation and our numerical simulations are a proof for that. On the edge of the flame Le is extremely low, which indicates that the flame accelerates. Flame can propagate with more than a speed of sound in the reactive mixture, which results in deflagration-to-detonation transition (DDT) and detonation. The present paper shows such propagating process with low Le as well as the profiles of Le in the DDT domain.
Lewis number, detonation, deflagration, DDT