No abstract

A Mach 13 operating point was achieved in the HYpersonic PULSE facility (HYPULSE) expansion tube and hydrogen injection studies were performed at this test condition. The experiments were conducted in a 2-x 1-in. combustor model employing three injector configurations: 1) a single, flush-wall, circular orifice; 2) two such orifices on opposite walls (the "dual" injector configuration); and 3) two orifices on the upper and lower walls (the "quad" injector configuration). The quad injectors were distinctly superior to the other two configurations in promoting mixing, ignition, and combustion. The single injector, however, proved to be. superior to the dual injectors, supporting the concept that the aspect ratio of the "injection cell" plays a large role in promoting the processes required to achieve high-combustion efficiency.