Numerical investigations on the influence of double ramps in a strut based scramjet combustor

This numerical study addresses the performance of double ramps in a strut injection scramjet combustor. Reynolds Averaged Navier Stokes (RANS) equations with the Shear Stress Transport SST k-omega turbulence model are used for numerical analysis. The dual ramps are located symmetrically at the top and bottom wall of a scramjet combustor downstream of the strut injector. The influence of the location of ramps in the scramjet combustor is analyzed based on the key parameters such as shock waves, static pressures, and temperature distribution across the combustor, which are verified with available DLR scramjet experimental data that show similar acceptable values within the range. Simulation is extended for the investigation of other configurations. The performance of the scramjet configurations has been analyzed using the variables such as shock patterns, Mach number contours, wall static pressures, mass fractions of the reactants and products, combustion efficiency, and stagnation pressure loss of combustor. Numerical shadowgraph indicates that numerous shock reflections occur for the dual ramp cases that decelerate the combustor's flow downstream. In addition, the recirculation regions are created for the dual ramp cases, which help in anchoring the flame. The static pressure distributions show the variation of peaks due to shock patterns and their interactions. The combustion efficiency increases as the ramps are positioned downstream of the strut injector. The mass fractions of reactants and products indicate complete combustion of the hydrogen issued from the combustor in the vicinity of the cavities. The total pressure loss for the DLR strut model is comparatively lower than dual ramp cases due to the multiple shocks from the ramp decelerating the flow downstream of the combustor.

Automated summary

This numerical study analyzes the performance of double ramps in a strut injection scramjet combustor. The results show that the dual ramps can decelerate the flow downstream of the combustor, creating recirculation regions that help in anchoring the flame. Additionally, the combustion efficiency increases as the ramps are positioned downstream of the strut injector.