Effects of inflow velocity on transverse jet injection in a supersonic cavity combustor

Abstract

The flow, mixing, and combustion mechanisms in the wide range scramjet engine are complex and far from clear. In the present work, the mixing flow of a sonic transverse jet injection in a supersonic cavity combustor is numerically investigated at two typical inflow velocities. The basic flow structures, unsteady flow dynamics, average flow structures, and several significant mixing performance parameters are well captured and compared based on high-resolution large eddy simulation. The simulation results show that separation shock induced by the jet is gradually merged with the bow shock at low Mach inflow so that the curved shock flow patter is produced. In addition, smaller large-scale coherent structures at the windward side and slower large-scale vortex transport are observed at low Mach inflow. At low Mach inflow, moreover, much narrower range of jet species mass fraction distributions and more upstream large-scale vortices breakdown and dissipation can be observed. The low Mach inflow generates weaker pair of counter-rotating vortices and some trailing counter-rotating vortices, which primarily leads to the weaker jet/cavity interaction. The baroclinic term effects are considerably weaker at low Mach inflow in the near field. In view of mixing efficiency and flammability efficiency, the effect of the cavity in enhancing mixing is more evident at low Mach inflow.