This research investigates the numerical analysis of a scramjet combustor, focusing on advanced hydrogen injection techniques to improve mixing and combustion efficiency. Simulations are performed using two-dimensional Reynolds-Averaged Navier–Stokes (RANS) equations, coupled with the Shear Stress Transport (SST) k–ω turbulence model and the finite-rate/eddy-dissipation reaction model. The injector configuration includes dual hydrogen slits within the strut and additional hydrogen injection through wall slits upstream of the combustor cavities. This study explores the impact of these injection setups on key performance indicators, such as fuel–air mixing, recirculation zone formation, and combustion efficiency. The results indicate significant improvements in mixing quality and flame stabilization, leading to enhanced combustion efficiency. These findings offer valuable insights for optimizing scramjet combustor designs to improve performance in hypersonic propulsion systems.