Effect of deflagration on detonation wave propagation characteristics and droplet breakup mechanism in a rotating detonation ramjet combustor

Liquid-kerosene-fueled rotating detonation ramjet engines are considered a promising next-generation powerplant for advanced aerial vehicles. However, recent studies have revealed that deflagration and detonation often coexist within the combustor. The presence of deflagration can interfere with the propagation of self-sustaining detonation waves. To investigate this phenomenon, this study employs the LagrDEFoam solver based on OpenFOAM V8® to conduct simulations examining the effects of deflagration on detonation wave propagation characteristics and droplet breakup processes in a rotating detonation ramjet combustor. The results show that the velocity deficit of detonation wave is attributed to the combined effects of deflagration ahead of the wavefront and incomplete fuel evaporation. Through a systematic analysis of the influence mechanisms of deflagration within the cavity shear layer and the expansion section recirculation zone, the role of deflagration in the detonation combustion process is further clarified. In addition, the detonation wave is found to significantly promote droplet breakup; when its intensity is attenuated by deflagration, the number of residual droplets behind the wave increases markedly.