Numerical study of the discrete staggered staged sonic jet interaction in a supersonic crossflow

Transverse slot injection has been widely investigated for hypersonic propulsion systems due to the ability to achieve a high degree of fuel-air mixing in supersonic flows in residence-time-limited supersonic combustors. In the present study, a new discrete staggered staged slot injection scheme is proposed, and is investigated in several aspects by solving three dimensional Reynolds-averaged Navier-Stokes equations along with Spalart-Allmaras one-equation turbulence model. The numerical method is first validated by comparing the predicted wall pressure distribution with the experimental data based on the grid independence study. Then, the three dimensional flow field of the discrete staggered staged slot injection is obtained and compared with that of the continuous single slot injection. The preliminary result shows that the current discrete staggered staged slot injection scheme outperforms the continuous single slot injection scheme in terms of the jet-crossflow mixing efficiency at a price of reasonable total pressure loss. Further, the effect of some relevant parameters (such as the number of discrete slots, the distance between the staged slots, the injection angle defined as the angle between freestream and jet) on the performance of the discrete staggered staged slot injection scheme is investigated. The configuration with discrete staged slot number of 4, staged distance of 5 mm and injection angle of 120° is the optimum choice for best performance under the present simulation conditions.