Propagation of Detonation Waves from an Energy Conservation Viewpoint

Abstract

The work reported here relates to the study of the propagation of selfsustaining detonation waves when such waves are not supported, in a nonsteady flow situation, by a flow of pressurized fluid behind the wave. The latter is the case for normal shock waves, of moderate strength without detonation, or with strong shocks perpetrating combustion when such shocks travel into combustible mixtures. The combustion process is normally of the Rayleigh type and occurs in a relatively thin layer behind the shock or detonation wave. For a self propagating, selfsustaining, detonation wave the work required to compress, progressively, each elemental layer of reactants has to be extracted from expansion, following combustion, of the layer immediately upstream of the layer downstream that has yet to be compressed and ignited by the propagating detonation wave. It is shown that a self-sustaining, self propagating detonation wave produces a situation which is essentially identical to that which would occur following constant volume combustion, of stationary reactants, in the combustion tube. Based on prior work by Foa it was found that the expanded material (products) produced by the detonation wave did not have sufficient energy to keep pace with the detonation wave and hence push the detonation wave to propagate at an even higher velocity than the very high velocity achieved by the detonation process.