Numerical investigation on a typical scramjet combustor using cavity floor H2 fuel injection strategy

The major issue in improving the efficiency of the scramjet engine is ensuring adequate hydrogen fuel distri-bution within the supersonic chamber. Recently cavity floor injection strategy is a promising approach to keeping the flame stable under an extensive range of operational conditions. Thus the present investigation involves the simulation of a scramjet combustor with cavity floor H2 injection technique under different free-stream Mach numbers using a computational approach. Our results indicate that as the free-stream Mach number rises; the circulations inside the cavity become more intense, resulting in the formation of a stable igniting zone inside the cavity. Next, the effect of different cavity floor length injection on the performance of the combustor has also been explored. The results obtained indicate an optimum cavity floor injection which can control the propagation of the shockwave in the downstream direction; or else, boundary layer separation may occur, resulting in even engine unstarts. For the present case, the optimum cavity floor length is found to be 45 mm.