Effects of the perturbation inlet on the evolution and oscillation characteristics of multiple rotating detonation waves

A numerical simulation using the open-source platform OpenFOAM is conducted to investigate the effect of periodic perturbations at the inlet on the evolution and oscillation characteristics of multiple rotating detonation waves (RDWs). The study uses a two-step chemical reaction mechanism of C2H4/Air. The results reveal that periodic perturbations have a significant effect on the pressure, detonation wave height, heat release rate, thrust, and specific impulse of the rotating detonation engine. The oscillation pattern of these parameters is found to be highly correlated with the form of the inlet perturbations. The study also examines the evolution mechanism of multiple detonation waves and identifies three primary propagation stages under inlet perturbations: chaotic propagation, self-adjustment, and oscillatory propagation. The multiple detonation waves originate from the chaotic propagation and are mainly adjusted in terms of the number and direction of detonation waves through the double-wave collision. The results demonstrate that increasing the amplitude of perturbations poses a significant risk to the survival of the RDW, while high-frequency perturbations may disrupt the three primary propagation stages, leading to predominantly the chaotic propagation. Furthermore, an analysis of the fast Fourier transform of the thrust and specific impulse shows that the oscillation forms of the specific impulse and thrust differ in the chaotic propagation stage. (c) 2023 Elsevier Masson SAS. All rights reserved.