A study of different injectors in a supersonic crossflow.

Scramjet or Supersonic combustion ramjet engine is the one of the most critical components in developing the air-breathing hypersonic air vehicles and has tremendous value in military or civil aerospace applications. One of the primary challenges in Scramjet engine development is enabling and maintaining a stable combustion process in a supersonic crossflow. At such high speed flow, achieving sufficient mixing between fuel and air/oxygen is extremely difficult, yet is essential for maintaining an efficient supersonic combustion. In this study, various injector designs were tested in a Mach 2 supersonic crossflow with helium as injected fluid. Using high-speed schlieren photography and a Global Luminescent Oil Flim method, the transient flow features and skin friction patterns were observed and captured, revealing distinct performance difference among injector designs.