Computational Investigation of Fuel Injection with Various Injector Geometries and Mixing into Hypersonic Crossflow in Scramjet Engines

Efficient fuel/air mixing plays a crucial role in successful operation of hypersonic airbreathing engines, particularly scramjets, where fuel must be injected into high-speed crossflow and mixed with air at an extremely short timescale. This paper presents the results of a numerical study that investigates the effects of various orifice shapes on fuel mixing into hypersonic airflow at Mach 5, aiming at the application to scramjet operation at Mach 10. The performance of the injectors are assessed with respect to various criteria such as the mixing efficiency, streamwise circulation, total pressure recovery, and fuel penetration. The injection flowfields are scrutinized in order to identify the key geometric features and underlying flow mechanism that are responsible for mixing enhancement, with particular focus on the interactions of the jet plume with streamwise vortices.