过渡型凹腔超声速燃烧流动振荡抑制方法

针对长深比为10.0的过渡型凹腔在隔离段入口马赫数为3.0条件下存在的冷流自激振荡现象，提出了一种凹腔内增加肋条抑制振荡的方案。通过试验和数值计算，对该方案抑制振荡的效果进行了检验，并分析了肋条增加前后燃烧室流场结构和燃烧性能的差别。研究发现：通过在凹腔内增加肋条能够消除过渡型凹腔冷流工况下存在的175.8 Hz的自激振荡，燃烧流场也更加稳定；增加肋条后凹腔的稳焰能力有所降低，部分在凹腔未完全燃烧的煤油进入扩张段后继续发生反应，从而使燃烧区向下游延伸、增大，发动机的燃烧效率和净推力分别降低5.4%和8.9%，但推力更加平稳；燃烧室一维平均热流密度峰值由2.9 MW/m²降低至1.8 MW/m²，燃烧室的热环境大幅改善。

Suppressing oscillation method of supersonic combustion and flow in transitional cavity

Targeting the phenomenon of non-reacting flow self-excited oscillation in a traditional cavity with a length-to-depth of 10.0 under the isolator entrance condition of Mach number 3.0, a scheme to suppress the oscillation by adding a rib in the cavity was proposed. Through experiments and numerical calculations, the effect of this scheme on suppressing oscillation was verified, and the differences in the flow field structure and combustion performance of the combustor with/without the rib were analyzed. It was found that adding a rib in the cavity can effectively eliminate the self-excited oscillation of 175.8 Hz under the non-reacting flow condition, and the reacting flow field was more stable. The flame stabilization ability of the cavity was reduced after the rib was added, and some kerosene not completely burned in the cavity continued to react after entering the divergent section, so as to extend and enlarge the combustion zone downstream. The combustion efficiency and net thrust of the engine were reduced by 5.4% and 8.9%, respectively, but the thrust was more stable. The peak value of one-dimensional averaged heat flux was also reduced from 2.9 MW/m2 to 1.8 MW/m2, which optimized the thermal environment of the combustor.