凹腔对固体超燃冲压发动机燃烧性能影响研究

Effects of Cavity on Solid Scramjet Combustion Performance

关键词:  固体超燃冲压发动机  凹腔  燃烧性能  直连试验  颗粒燃烧  数值模拟

Key words:  Solid scramjet  Cavity  Combustion performance  Direct-connect tests  Particle combustion  Numerical simulation

摘要:

为提高固体超燃冲压发动机燃烧性能，获得凹腔对固体超燃冲压发动机燃烧性能影响规律，开展了地面直连试验和数值模拟研究。利用数值模拟分析了凹腔位置和数量对燃烧室流动与富燃燃气掺混燃烧作用效果。研究表明：（1）马赫数沿燃烧室流向均呈现下降-波动-上升的变化特点，相比于无/单凹腔构型中的近壁面燃烧，双凹腔构型实现流道中心燃烧。（2）富燃燃气中可燃气体与凝相颗粒因穿透深度不同导致两者分区燃烧，气相燃烧速度和燃烧效率均远高于凝相颗粒，不同质量的颗粒运动轨迹存在差异，但该差异随颗粒燃烧而逐渐减小。（3）凹腔通过产生低速区促进富燃燃气掺混燃烧，促进效果取决于凹腔与燃气喷口间的距离。（4）凹腔对固体超燃冲压发动机燃烧性能具有明显影响，发动机无凹腔时燃烧效率仅0.48，总压损失达0.67，采用双凹腔时燃烧效率达0.98，总压损失为0.58。综上所述，采用双凹腔构型的燃烧室更有利于提高固体超燃冲压发动机燃烧性能。

Abstract:

In order to improve the performance and obtain the effects of the cavity on the combustion efficiency of the solid scramjet， direct-connect tests and numerical simulation were carried out. Numerical simulation is used to analyse the effects of the position and number of cavities on the combustor flow and the fuel-rich mixture combustion. The results show that： （1） The Mach number along the flow direction of the combustor all presents the characteristics of decreasing-fluctuating-rising. Compared with the near-wall combustion in the non/single-cavity configuration， the two-cavities configuration realizes the combustion at the central area of the channel. （2） The combustible gas and condensed particles in the fuel-rich mixture are burnt in different areas due to the different penetration depths. The gas combustion speed and combustion efficiency are much higher than those of the particles. Particles of different masses have different trajectories， but the difference gradually becomes smaller as the particles burn. （3） The cavity promotes the mixing and combustion of the fuel-rich mixture by creating a low-speed zone， and the promotion effect depends on the distance between the cavity and the fuel-rich mixture jet. （4） The cavity has a significant impact on the combustion efficiency of the solid scramjet. When there is no cavity， the combustion efficiency is only 0.48 and the total pressure loss is 0.67， while when the two-cavities are used， the combustion efficiency is 0.98 and the total pressure loss is 0.58. In conclusion， the two-cavities configuration of the combustor is more conducive to improving the combustion performance of the solid scramjet.