Molecular weight and injector configuration effects on the transverse injection flow field properties in supersonic flows

The transverse injection flow field in the high speed conditions is more complex than that in the low speed, and more information should be explored to improve the overall performance of the airbreathing hypersonic propulsion system. The three-dimensional Reynolds-averaged Navier–Stokes (RANS) equations and the two equation SST k–ω has been employed to explore the influences of the molecular weight (hydrogen and nitrogen) and injector configuration (circular, square, diamond and equilateral triangular) on the mean flow field properties in the transverse injection strategy, and the wide range of the jet-to-crossflow pressure ratio (4.86, 10.29, 17.72 and 25.15) has been considered as well. The obtained results show that the low jet-to-crossflow pressure ratio can promote the mixing process between the injectant and the supersonic crossflow irrespective of the injectant species and the injector configuration, and the large molecular weight of the injectant can promote the mixing process as well when the jet-to-crossflow pressure ratio is fixed. The case with the equilateral triangular injector owns the highest mixing efficiency in the range considered in the current study, and it may be induced by the remarkable influence of the counter-rotating vortex pair. The injectant mole fraction decreases more rapidly with the increase of the streamwise distance for the case with the low jet-to-crossflow pressure ratio, and the jet plume spreads in the spanwise direction more rapidly for the case with the diamond injector irrespective of the injectant species.