Supersonic Combustion Using a Stinger-Shaped Fuel Injector

Abstract

We 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-tocrossflow 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 coldflow 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 the advantage of the injector for jet penetration. The injector, however, produced higher pressure thrust because better flame-holding produced higher pressure around the injector. At a higher Φ regime, the precombustion shock wave went upstream with both injectors. The far-upstream presence of a precombustion shock wave increased the

Supersonic Combustion using Multiple Stinger-shaped Injectors

“…During dual-mode operation, the effect of injector-port shape was insignificant to the thrust even for the single injector case. 9) This was similar to the result for the multiple injector cases. Figure 6 presents the exit cross-sectional º and c distributions at È ¼ 0:20.…”

“…9) This was higher than that for the multiple injector case (P W;ST =P W;CR $ 1:05). The effect of the injector shape in the multiple injector case was smaller than that for the single injector case.…”

“…The typical uncertainty in º is 2% and that in c is 3% around º of unity. See Kouchi et al 9) for details on the measurements and their uncertainties.…”

“…We experimentally confirmed that the performance of a combustor with a stinger injector installed is much higher than that with a conventional circular injector. 9,10) In the series of experiments, we only considered single-injector configurations.…”

“…The geometrical shape of each stinger port is the same as the previous one. [8][9][10] The center-to-center spacing of the injectors (s) was set to be 20 mm with the four injectors oriented to have equal spacing for the combustor width (94.3-mm-width/5 intervals for 4 injectors). This corresponded to s=D $ 6:7.…”