Influence of Incident Shocks on Flame Characteristics in the Strut-Equipped Supersonic Combustor

Abstract

In this paper, under incident shock waves, the flame characteristics of the strut-equipped supersonic combustor fueled by liquid kerosene are investigated by numerical simulation and experimental means in operating cases of Mach [Formula: see text]. During this process, the Mach number at the combustor entrance varied from 2.0 to 2.8, and a 14 deg wedge was installed at the isolator inlet as an incident shock simulator. A position-adjustable thin strut was used to optimize the ignition efficiency, and flame propagation was captured and reproduced using a visualization window mounted on the combustor side wall. The conclusions drawn from the study could reduce potential hazards for flight experiments. The simulation found that with the addition of the incident shock wave, the asymmetric shock wave system and the discontinuous acceleration regions were formed in the initial flowfield, which caused the relative position between the strut and wedge to have a significant effect on ignition. Experiments showed that when the two were mounted on the same side, the incident shock wave weakened the ignition conditions, preventing the formation of a global flame within the combustor. After changing the wedge installation direction and reducing the inlet Mach number, the effect of the flame characteristics affected by the incident shock wave was easier to capture. The flame kernel [Formula: see text] appeared at the strut tail, the combustion heat release area became more concentrated, and the flame development was accelerated. The results showed that the incident shock wave kept the flame oscillation frequency around 170 Hz, and the combustor pressure rise performance in the steady state was almost unchanged. Overall, the ignition delay of the combustor is increased, but the engine thrust is hardly affected by comparison with the ideal situation.