Tailored fuel injection within a Mach 12 shape transitioning scramjet

Three-dimensional computational fluid dynamic simulations were performed for the Mach 12 Rectangular-to-Elliptical Shape-Transitioning scramjet. Present injector arrangements at the combustor entrance displayed low jet penetration, resulting in a oxygen-based combustion efficiency of 84.9%. It is proposed to convert three cowl-side injectors into one larger injector located further upstream. To support this, injector configurations were investigated computationally, taking injectors optimised for penetration at lower Mach numbers, and evaluating their performance at higher Mach number flight conditions. It was determined that reduced performance of these optimised injectors was encountered at scramjet flight conditions above their design point, with circular injectors at equal or greater injection angles displaying greater penetration and mixing capabilities.