Numerical research on the non-premixed two-phase kerosene/air ramjet rotating detonation engines with divergent isolators

In this paper, the Eulerian–Lagrangian method was employed to simulate a non-premixed two-phase ramjet-rotating detonation engine with divergent isolators. The impact of the isolator lengths and inlet widths on the dynamics of the rotating detonation wave and the propagation of the upstream oblique shock wave is analyzed. The simulation results show that the upstream oblique shock wave can propagate upstream into the isolator, and there are two main propagation modes: penetration and suppression. The total pressure loss will occur when the flow passes through the upstream oblique shock wave. Generally, at the same isolator length, the smaller the inlet width, the greater the total pressure loss. In the case of the upstream oblique shock penetrating the isolator, the total pressure loss occurs before the isolator, which leads to the fact that the total pressure loss cannot be reflected in the result. In the short isolator, the Mach number will increase when reducing the isolator inlet width. This phenomenon will generate a normal shock in the divergent station. Therefore, the total pressure loss will increase after the divergent station, and the strength of the upstream oblique shock wave will be weakened, which is conducive to suppressing the upstream oblique shock wave. In the longer isolator, the upstream oblique shock wave can be suppressed. The propagation modes of the upstream oblique shock wave in the ramjet rotating detonation engine with divergent isolators can be predicted by the critical pressure ratio βcr3.