Investigation of Key Factors Influencing Dynamic Detonation Stabilization in a Supersonic Model Combustor

The dynamic stabilization of detonation waves is critically governed by two factors: the incoming flow Mach number and the combustor geometry. This study investigates their combined role using high-fidelity numerical simulation. We specifically analyze a configuration featuring a cavity and an expansion wall. The objective is to elucidate the mechanisms through which these geometric elements interact with the flow to promote sustained detonation above the Chapman-Jouguet (CJ) velocity. The two-dimensional reactive Navier – Stokes equations coupled with a one-step, two-species reaction model are solved using a hybrid sixth-order Weighted Essentially Non-Oscillatory Central Difference (WENO-CD) scheme within a Structured Adaptive Mesh Refinement (SAMR) framework. This high-fidelity computational approach captures the essential shock waves, contact discontinuities, and fine-scale reaction zones with high resolution and minimal numerical dissipation, making it well-suited for simulating the intricate physics of detonation stabilization. The results demonstrate that a combustor configuration incorporating a cavity and an expansion wall promotes dynamic detonation stability. Specifically, the Prandtl – Meyer expansion fan and large-scale vortices generated by the expanding wall, along with pressure oscillations from the cavity, enhance the consumption and heat release of the unburned jet, thereby sustaining detonation. The incoming Mach number is found to critically influence stability: detonation waves cannot stabilize below the Chapman – Jouguet (CJ) velocity, but can be stabilized above it through the combined effects of the cavity and expansion wall. Additionally, geometric parameters such as the expansion wall angle and cavity dimensions significantly affect the stability and location of the detonation wave. Increasing the expansion angle extends the unburned jet and attenuates detonation, while altering cavity size and position influences pressure oscillations and combustion efficiency, thereby modulating the duration and degree of wave stability. This highlights the need for careful geometric optimization to achieve desired operational characteristics, balancing the reinforcement mechanisms from the cavity with the flow-turning effects of the expansion.