Numerical investigation of the pressure gain obtained by the double-stage JP-10/air detonation wave

Abstract

In this study, a double-stage detonation system is proposed to achieve higher pressure gain. The first-stage detonation transforms into a shock when it passes through a thin inert layer. Subsequently, this shock compresses the second-stage unburnt mixture, increasing its initial pressure. Finally, the second-stage detonation is initiated, resulting in higher pressure gain. One- and two-dimensional transient numerical simulations of the JP-10/air detonation wave are conducted, coupled with the global reaction model developed by the authors. The numerical model and methods are validated by comparing the combustion and detonation properties with both detailed reaction kinetics and experimental data. The results demonstrate that the peak pressure of the second-stage detonation wave is twice as high as that of the first-stage detonation wave. This finding proves that compared to a single detonation wave, higher pressure gain can be achieved by implementing the current double-stage detonation wave. To address the complexity arising from multi-detonation initiation, the second-stage detonation combustor is optimized by achieving detonation self-initiation through shock focusing. Numerical simulations further confirm the feasibility of this process. The results indicate that the detonation pressure near the shock focusing zone is much higher than in the rest of the zone, and the detonation is in an over-driven state during the early stages after shock focusing.