Thermo-acoustic instability in the process of flame propagation and transition to detonation

The paper is devoted to the numerical analysis of the reactive mixture explosion during the accidents at a launch site. The particular scenario concerns the explosion in the unconfined volume after accidental fuel release into the atmosphere. It is shown that the development of intrinsic flame instability results in the generation of compression waves, which occur to be intensified via the mechanism of thermo-acoustic instability. In turn, intensification of the compression waves leads to the formation of strong shock waves and even detonation in the case of a highly reactive mixture. The leading role in this process belongs to the transversal waves generated in the folds of the developed flame surface and propagated along the flame surface. It is the localization of the compression wave inside the reaction zone that causes amplification of the compression wave due to energy release.