Supersonic Combustion Using a Stinger-Shaped Fuel Injector

The authors developed a stinger-shaped injector (stinger injector) for supersonic combustors in cold-flow experiments. The stinger injector has a port geometry with a sharp leading edge in front of a streamwise slit. This injector produced higher jet penetration at a lower jet-to-crossflow momentum flux ratio J than a conventional circular injector. We applied the injector in a Mach 2.44 combustion test at a stagnation temperature of 2060 K. At a low fuel-equivalence ratio Φ regime (i.e., low J regime), the injector produced 10% higher pressure thrust than the circular injector because of high jet penetration as expected from the cold-flow experiments. Even at a moderate Φ regime, the stinger injector produced higher pressure thrust than the circular injector. At moderate Φ, the stinger injector held the flame around the injector and generated a precombustion shock wave in front of the injector. The presence of the precombustion shock wave decreased the momentum flux of the crossflow air and diminished th...