Numerical research on the propagation characteristics and evolution mechanisms of rotating detonation waves with the spatial fluctuation of inlet total pressure

The stable combustion of rotating detonation engines is significantly affected by inlet spatial fluctuation, especially during aircraft maneuvering, necessitating extensive research for further engineering enhancements. This study analyzes the effect of the spatial fluctuation of inlet total pressure on the propagation characteristics and evolution mechanisms of rotating detonation waves. The in-house solver, BYRFoam, based on the OpenFOAM platform, is utilized. The velocity deficit of detonation waves is discussed under the different inlet spatial fluctuations of mean total pressure, instability degree, and spatial frequency. The results indicate that the propagation process of detonation waves is divided into wave mode transition and operating mode-locked stages; the latter consists of the self-adjustment stage, low-frequency instability stage, and dynamic equilibrium stage. A dynamic equilibrium mechanism is proposed, which is the self-adjustment process of detonation waves, counter-rotating shock waves, and striped fresh gas, encompassing the stages of strong and weak detonation. Furthermore, the oscillation phenomenon of the peak pressure, frequency, and velocity of detonation waves is seriously related to spatial fluctuation, leading to instability during detonation wave propagation. The instability phenomenon in this study is compared with the experimental data, providing valuable theoretical support for engineering applications involving rotating detonation engines.