Mixing and Combustion Enhancement in a Mach 12 Shape-Transitioning Scramjet Engine

Despite being an active topic of research for over 50 years, scramjet technology has only recently matured to a point where flight tests are being successfully carried out at the lower end of the hypersonic regime. While this progress is encouraging, a re-newed interest in low-cost, reliable, and environmentally responsible access to space has identified scramjets capable of accelerating to speeds as high as Mach 12 as de-sirable. One class of scramjets thought to be capable of hypervelocity performance are those that employ three-dimensional streamtraced compression inlets to efficiently compress captured air. One promising example of this type of scramjet is the Mach 12 Rectangular-to-Elliptical Shape-Transitioning (REST) engine. The aims of this study are to investigate and characterize the flow physics behind the Mach 12 REST engine’s current performance, and then attempt to improve its combustion performance by tai-loring the engine’s fuel injection to its internal flow field without otherwise modifying the engine geometry. To meet these aims, the engine was studied both numerically and experimentally