Effects of Ramp-Induced Incident Shock Impingement Under Various Slope Angle Configurations in a Strut-Based/Cavity-Assisted Supersonic Combustor

Abstract

ABSTRACT The present study conducts a numerical investigation into the effects of ramp-induced shock impingement with different opening angles on the global flow-field and combustion behaviors within a strut-based/cavity-assisted scramjet combustor. To reproduce the intricate physical phenomena and all inflow properties of the primary channel, two-dimensional Reynolds-averaged Navier–Stokes (RANS) equations integrated with the shear stress transport (SST) k − ω turbulence model is implemented. The current approach considers several slope angle configurations of the ramp since they generate various shock systems that differ in magnitudes and coherent structures, substantially affecting the combustion efficiencies and chemical species distributions. Results reveal that an optimal shock angle of the ramp in correspondence with the current operating conditions can be achieved at 20°, which increases the combustion efficiency by 11% at the end of the cavity trailing edge without provoking excessive loss of total mass-flux-weighted pressure recovery. However, further expanding the slope angle above the optimum will trigger the flow blockage mechanism which enlarges the recirculation region on both sides of the ramp, simultaneously initiate their local thickening processes and create shock train areas owing to intensive interactions with the turbulent boundary layers. These phenomena are known for decreasing the total pressure ratio, adversely affecting all performance metrics of interest and destabilizing the main channel flow path.