Effects of injection conditions on the stability of rotating detonation waves

This article presents a numerical investigation of a rotating detonation engine (RDE). The simulation explores the instability mechanism of detonation waves in the RDE with micro-convergent-nozzle injection. The process is modeled by the two-dimensional reactive Euler equations with detailed chemical reaction kinetics for the injection of premixed stoichiometric hydrogen-air. The numerical results show an interesting instability phenomenon whereby an unstable detonation wave rotates circumferentially at the fuel injection head of the chamber. The shape of the fresh fuel layer is irregular, which is different from that in previous numerical simulations. The height and strength of the detonation wave are periodically fluctuating, as well as the mass flow rate of the reactants into the chamber. Based on the time evolution of the detonation wave, it is found that the detonation wave oscillates due to the interaction of fuel injection and weak transverse shock waves following the detonation wave. The detonation wave, the shape of the fresh fuel layer, and the mass flow rate influence each other. Therefore, this oscillation remains in the flow field, as does the instability of the detonation wave. This finding is in good agreement with previous experiments.