Combustion performance of supersonic combustor with stinger-shaped fuel injector

Supersonic combustor with single "stinger-shaped" injector or multi ones arranged side-by-side in the spanwise direction were tested in a direct-connect wind-tunnel facility at a Mach 2.5 with a stagnation condition of 1.05 MPa and 2060 K. The stinger-shaped injector, having sharp leading edge followed by a streamwise slit, produced higher jet penetration in the height-wise direction as compared with the circular injector case at low jet dynamic pressure regime in our previous cold flow tests. In the combustion test, the single stinger-shaped injector produced higher jet penetration, resulting in 10 % higher thrust than the circular case when combustion region was limited in the diverging-area combustor. This injector also provided higher thrust even when flame was anchored around the injector with increasing fuel equivalence ratio (i.e. jet dynamic pressure), though the penetration reduced. This was because the stinger-shaped injector had better flame-holding performance near the injector. In the multi injector case, even with the stinger-shaped injector, the plume growing in the vertical direction, the adjacent fuel jets merged and the large plume was formed. The advantage of the stinger shape was diminished. The thrust performance in the stinger case, however, remained higher than that in the circular case.