Wave Shaping Channels for Gaseous Detonations

The problem of detonation wave shaping by converging channels was investigated computationally and experimentally. Whitham's method of shock dynamics, extended to gaseous detonations, was used to design a converging channel to produce an overdriven, planar detonation. The channel was designed for a detonation in a stoichiometric oxygen-acetylene mixture with an inlet Mach number of 7.3 and an exit Mach number of 7.8, corresponding to an overdrive ratio of 1.07. It was tested experimentally at initial pressures ranging from 15 to 60 Torr. Soot foil records indicate smooth wavefronts with a gradual decrease in detonation cell-width along the channel. The overdrive ratios, estimated from changes in cell size, ranged from 1.01 to 1.05.