Numerical Investigations of Detonation Induced by Implosion Flame inResonator Cavity

Based on the two-dimensional axisymmetric Euler equations coupling with chemical reactions, the phenomena of implosion combustion for hydrogen-air mixture were numerically studied by using wave propagation algorithm with Superbee limiter in resonator cavity. The effects of resonator shapes on initiation and detonation were discussed. Results show that the shock wave induced by combustion firstly reflected back and forth from walls and the axis of the resonator cavity, which led to multiple the shock-flame interactions and enhanced the flame combustion. Then the reflected shock wave produced by the parabolic reflector in resonator cavity frequently penetrated the flame, which led to continuous flame excitation. Finally, DDT occurred. Simultaneously, the repeated shock-flame interactions caused the instability and distortion of the flame, and then formed asymmetrical collapsing of the flame front. The different shapes of reflector caused the change of focus, which could influence the shock-flame interaction and made detonation onset change, even not occurred.