凹腔对含硼固体火箭超燃冲压燃烧特性的影响

凹腔常用来增强超燃冲压发动机中空气与燃气掺混、提升火焰稳定性及燃烧效率，然而超音速燃烧室内的燃气流场特性依赖于凹腔结构及其分布。为优化凹腔结构及其分布，提升固体火箭超燃冲压发动机补燃室内的燃烧性能，采用数值方法计算分析凹腔长深比、后倾斜角对含硼固体火箭超燃冲压发动机燃烧特性的影响。计算结果表明：在凹腔长度不变时，取凹腔长深比分别为5.00、3.75、3.00、2.50、2.18、1.85、1.67，硼颗粒燃烧效率与比冲随着长深比减小先增大、后减小，在长深比为1.85时最大；当凹腔长深比为1.85、凹腔后倾角从90°变化到175°时，随着凹腔后倾角增加，硼颗粒燃烧效率增加，175°时燃烧效率最大，但其总压恢复系数及比冲最小，比冲在165°时最高。

Effect of Cavity on Scramjet Combustion Characteristics of Boron-containing Solid Rocket

Cavity is often used to enhance the mixing of air and gas in scramjet，and improve the flame stability and combustion efficiency. The characteristics of flow field in supersonic combustor depend on the structure and distribution of cavity. In order to optimize the cavity structure and its distribution，and improve the combustion performance of secondary combustion chamber in solid rocket scramjet，the effects of cavity length-to-depth ratio and rear tilt angle on the combustion characteristics of boron-containing solid rocket scramjet were studied by numerical method. The calculation results show that, when the cavity length is constant and the length-to-depth ratios of cavity are 5，3.75，3，2.5，2.14，1.85，1.67，respectively, the length-to-depth ratio of cavity is 1.85，and the combustion efficiency and specific impulse of boron particles are the highest. When the length-to-depth ratio of cavity is 1.85，and the rear tilt angle of cavity is changed from 90° to 175°， the combustion efficiency of boron particles increases with the increase in the tilt angle. When the rear tilt angle is 175°，the combustion efficiency of boron particles is the highest，but the total pressure recovery coefficient and specific impulse are the smallest. And the specific impulse is the highest when the rear tilt angle is 165°.