关键词: 冲压喷气发动机;突扩燃烧室;水动力模拟;振荡燃烧;抑制;流场显示

Abstract: Vortex instablity in combustor flow field is an iynportant reason which leads to combustion oscillation in a side dump combustor. Flow visualization experiments were performed in a transparent rectangular combustion chamber model. Oscillation vortex system and non-oscillating vortex system were found from experiments. A highly stable vortex was found in the head of the combustor. ’Horseshoe’ vortex shedding periodically occur in the shear layer of the inlet jet flow. Asthe jet spread crosswisely through the passage of the combustion chamber, a pair of belieal vortex curlled up with a strong vortex intensity. Owing to the colliding of the vortex-pair, belieal columnar vortex become mis-stability and oscillation, then it smashed. With the injection of the secondary flow, the ’horseshoe’ vortex was smashed, vertex disturbance at the tail of the potential core of the jet flow was eliminated. Next, the belieal columnar vortex get enough the vorticity supplied by the crosswise spread of the secondary jet flow to rotate stably. Meanwhile, the combustion oscillation was removed or decreased. Cold flow field computations based on Simple method to solve the steady state mean flow equations with a two-equation(k-ε) model of turbutence was performed for the side dump combustor and the side dump combustor with secondary flow injection. The results are in good agreement with those of the water tunnel flow visualization results, except the periodic and unstable flow.

Key words: Ramjet engine;Dump combustion chamber;Hydrodynamic simulation;Vibrational combustion;Suppression;Flow visualization