Detonation Dynamics in a Curved Chamber for an Argon Diluted Hydrogen-oxygen Mixture

The dynamics of detonation transmission from a straight channel into a curved chamber was investigated as a function of initial pressure using a combined experimental and numerical study. Hi-speed Schlieren and *OH chemiluminescense were used for flow visualization; numerical simulations considered the two-dimensional reactive Euler equations with detailed chemistry. Results show the highly transient sequence of events (i.e. detonation diffraction, re-initiation attempts and wave reflections) that precede the formation of a steadily rotating Mach detonation along the outer wall of the chamber. An increase in pressure, from 15 kPa to 26 kPa, expectedly resulted in detonations that are less sensitive to diffraction. Local quenching of the initial detonation occurred for all pressures considered. The location where this decoupling occurred along the inner wall determined the location where transition from regular reflection to a rather complex wave structure occurred along the outer wall. This complex wave structure includes a steadily rotating Mach detonation (stem), an incident decoupled shock-reaction zone region, and a transverse detonation that propagates in pre-shocked mixture.