Numerical investigation of cavity-induced enhanced supersonic mixing with inclined injection strategies

In this study, an inclined injection system with a cavity and grooves arranged in series is developed to enhance the supersonic mixing in a scramjet combustor. Three-dimensional steady Reynolds-averaged Navier-Stokes equations, the two-equation shear stress transport k-omega model, and the finite-rate/no turbulence-chemistry interaction model are used to simulate the flow field structures with and without grooves at different inclination angles. The numerical method used in the study has been verified using experimental data from the open literature, and the static wall pressure distribution of the numerical simulation is in good agreement with the experimental data. The numerical results reveal that the grooved configuration has a significant influence on the flow field structure. The downstream streamline of the structure with grooves is more turbulent and produces more streamwise vortices because the geometry of the grooves enhances the shear effect between the vortex and the high-speed incoming flow. In the case of the grooved configuration, the mixing coefficient at the fuel orifices is slightly lower, but the fuel mixing effect in the downstream is enhanced and gradually exceeds the grooveless configuration. Moreover, the grooved configuration can obtain the best mixing coefficient at a jet angle of 30 degrees. The grooved configuration has a greater stagnation pressure loss than the grooveless configuration.