Investigation on operating characteristics of solid fuel-rich gas rotating detonation engine

ABSTRACT While hydrocarbon solid fuel-rich propellants possess high energy density and reliability, the resulting fuel-rich gas contains a significant fraction of low-detonability components, posing severe challenges to detonation initiation and self-sustained propagation within the multiphase flow field. Therefore, this study evaluates the effects of oxidant oxygen content and fuel-rich gas mass flow rate on the operating characteristics of a rotating detonation engine through direct-connect experiments, aiming to deepen the understanding of the detonation mechanisms of solid fuel-rich gas. Results indicate that initiation of the fuel-rich gas and pure air mixture was unattainable within the current combustor configuration. As the oxygen content increased to 32.7%, the system established an unstable single-wave mode. When the oxygen content reached 35.9% and above, instantaneous initiation and stable self-sustained propagation were achieved, with an auto-initiation phenomenon triggered at 40.0% oxygen content. All experimental cases followed a single-wave propagation mode, where the wave velocity increased and then decreased with the gas mass flow rate, peaking at 1460.48 m/s under the optimal mixing state. Furthermore, with the increase in total mass flow rate and the improvement of mixing efficiency, the overall energy density and momentum flux within the flow field increased significantly, driving the thrust to reach 1025.8 N under the optimal operating condition. This study reveals the detonation evolution laws of solid fuel-rich gas and provides key technical support for the engineering application of such engines.