Self-sustaining and evolution mechanisms of rotating detonation under high-total-temperature supersonic inflow

This study investigates the self-sustaining and evolution mechanisms of rotating detonation waves (RDW) under high-total-temperature supersonic inflow at different initial temperatures. Theoretical models are first employed to systematically analyze the influence of initial temperature on the detonation wave. Higher initial temperatures lower the propagation velocity, pressure, and peak heat release rate (HRR), indicating a relatively weaker detonation wave. Meanwhile, they reduce both the induction time and the density ratio, thereby promoting the backward propagation of perturbations into the subsequent cycle. Numerical simulations well corroborate these trends. The results show that as temperature increases, the detonation mode changes from a co-propagating triple-wave mode to a counter-propagating multi-wave mode. For the co-propagating triple-wave mode, the self-sustaining location of the RDW shifts downstream, and its circumferential propagation velocity drops. For the counter-propagating multi-wave mode, perturbations more easily trigger new RDWs, especially counter-propagating ones, thereby raising the collision frequency. Detonation combustion mainly concentrates in zones of high HRR and high tangential velocity. With rising temperature, the fuel consumed in the high-HRR/high-tangential-velocity region decreases, while that in the low-HRR/high-axial-velocity region increases; however, the tangentially propagating waves and their collisions continue to control the overall flow field. Finally, statistical analysis is conducted to assess the variation in performance over the investigated temperature range. Despite differences in isolator inlet temperature and Mach number among the cases, the combustor exit parameters remain similar. As the temperature rises, the cross-sectional mass-averaged HRR and total pressure loss both decline, and the combustor exit pressure drops, resulting in lower thrust and specific impulse. The trends revealed by the statistical analysis align with those predicted theoretically. These findings establish a fundamental framework for studying rotating detonation engines under high-total-temperature supersonic inflow conditions applicable to high-Mach-number propulsion.