High-speed flame propagation in a channel and transition to detonation

The physical mechanisms controlling the development of a flame prior to transition to detonation in a channel filled with a combustible gaseous mixture are systemized and analyzed. The features of the development of the accelerated flame in a channel are demonstrated with the results of numerical simulation for smooth and obstructed channels. This analysis makes it possible to formulate the criteria for a detonation onset induced by the development of an accelerated flame. Estimations on the basis of the proposed criteria predict with reasonable accuracy the limits of detonation initiation in hydrogen-based combustible mixtures.