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为研究并联凹腔火焰稳定器的超声速燃烧特性,通过在凹腔上游喷注乙烯,采用单边扩张型燃烧室在当量比φ=0.43~1.07内进行了一系列直连式燃烧试验。模型燃烧室入口参数为Ma=3.46,总温Tt=1430K。基于燃烧室壁面静压分布、推力增益、燃料比冲和燃烧流场的可见光与纹影图像分析了并联凹腔在不同当量比下的火焰结构、流场特征和燃烧性能。结果表明,上、下壁面凹腔附近的流动条件差异显著,燃烧过程与当地流动条件之间的强烈耦合作用使得燃烧室内火焰分布显著不对称。发动机燃烧性能对当量比十分敏感,壁面静压水平和推力增益随当量比增加持续升高,但φ=0.43~0.62时的增加速率远大于φ=0.76~1.07时的。φ=0.43~0.62时,燃料比冲和燃烧效率随当量比增加而升高;而φ=0.76~1.07时,燃料比冲和燃烧效率随当量比增加而降低。
In order to study the supersonic combustion characteristics of the parallel cavity flame stabilizer, a series of direct combustion tests were carried out in the equivalence ratio φ = 0.43 ~ 1.07 by injecting ethylene upstream of the cavity. The model combustion chamber inlet parameters for the Ma = 3.46, the total temperature Tt = 1430K. The flame structure, flow field characteristics and combustion performance of the parallel cavity at different equivalence ratios were analyzed based on the visible and smear images of static pressure distribution, thrust gain, fuel ratio impulse and combustion flow field on the wall of the combustion chamber. The results show that there are significant differences in the flow conditions near the upper and lower wall cavities, and the strong coupling between the combustion process and the local flow conditions makes the flame distribution in the combustion chamber significantly asymmetric. The combustion performance of the engine is very sensitive to the equivalence ratio. The static pressure level and the thrust gain of the wall surface continue to increase with the equivalence ratio, but the increasing rate of φ = 0.43 ~ 0.62 is much larger than that of φ = 0.76 ~ 1.07. When φ = 0.43 ~ 0.62, the specific impulse and combustion efficiency of fuel increased with the equivalence ratio increase, while the specific impulse ratio and combustion efficiency decreased with φ = 0.76 ~ 1.07.