On metastable deflagration in porous medium combustion

A regime of low velocity deflagration in hydraulically resisted flows such as those occurring in porous beds is discussed. An asymptotic expression for the deflagration velocity is derived. The obtained dependency elucidates the mechanism controlling the gradual enhancement of the propagation velocity prior to the abrupt transition from slow to fast combustion. This enhancement is caused by the drag-induced diffusion of pressure ahead of the advancing front. The time of transition from the slow to fast propagation is estimated.