Effects of Shock Waves, Boundary Layer and Turbulence on Flame Acceleration and DDT in Highly Reactive Mixtures (original) (raw)

The problem of the deflagration-to-detonation transition (DDT) and a key role of shock waves, boundary layer and turbulence in the detonation preconditioning process is well known but still not resolved in the combustion theory. The ignition, flame propagation with a flow ahead of the flame, and shock waves generation with turbulent boundary layer behind the shock is the sequence of principal events leading to the deflagration-to-detonation transition in smooth channels [1-3]. As Ya. Zeldovich wrote [4], the turbulence is not only one and even not the major reason of the flame acceleration in smooth channels. Wrinkled flame stretch and non-uniformity of the flow across the channel can be the main reason of flame acceleration leading to DDT. Experimental schlieren photos indicated that location of the transition to detonation always originates somewhere within the shockwave complex, sometimes near the wall in the boundary layer, sometimes in the center of a channel. One of the main p...