Investigation on the impact of the induced shock wave on the hydrogen mixing augmentation in a supersonic crossflow: A numerical study

The mixing process between the fuel and the incoming air flow plays an important role for the engineering implementation of a scramjet engine. In the current study, the shock wave/jet shear layer interaction approach is utilized to promote the hydrogen mixing enhancement in a supersonic flow. The action location between the induced shock wave and the air inflow, as well as the intensity of the shock wave, is investigated to capture the mixing enhancement mechanism. Some parameters are provided to evaluate the flow field properties quantitatively, namely the mixing efficiency and the total pressure recovery coefficient. The obtained results predicted by the three-dimensional Reynolds-average Navier-Stoke (RANS) equations coupled with the two-equation shear stress transport (SST) kappa-omega turbulence model show that the shock wave/jet shear layer interaction approach can effectively improve the mixing efficiency. The mixing speed and the mixing efficiency both increase with the increase of the intensity of the shock wave. The mixing enhancement mechanism is that the enhancement of the streamwise and spanwise vorticity upstream of the jet promotes the enlargement of the upstream separation zone and recirculation zone. When the shock wave position moves downstream, the spanwise vorticity increases, and the downstream recirculation zone increases significantly to promote mixing.