Abstract: On the basis of comparison with experimental data verifying the reliability of model， two-dimensional axisymmetric numerical model with secondary combustion and trail cover movement was established for double pressure peaks shock of missile low-temperature gas-ejection. The flow field mechanism of the ring cavity smoothing missile bottom pressure curve was studied， and the influence of structural parameters on the pressure impact smoothing effect was analyzed by decoupling， and the idea of ordinal optimization was put forward. The numerical results show that the ring cavity with the function of storage of oxygen can effectively prevent gas from diffusing upward， making the secondary combustion expand along the time dimension， thereby smoothing the impact of missile bottom. After the arrangement height and annular radius of ring cavity are established by geometric constraints of initial chamber space， the length can be taken as the main structural parameters to control the curve of missile bottom pressure， and expansion or contraction of angle as the structure parameter to fine tune， then the pressure curve can approximate the ideal design curve. After arranging the optimal ring cavity， the peak acceleration is reduced by 9.26%， and out of the cylinder speed is reduced by 4.13%， and out of the cylinder time is extended by 2.5%.

Key words: Gas-ejection；Pressure shock；Ring cavity；Interior ballistic；Flow field；Load

摘要： 针对导弹低燃温弹射压力双波峰冲击的问题，建立了含二次燃烧和尾罩运动的二维轴对称数值模型，在与实验数据对比的基础上验证了模型可靠性。研究了环形腔平滑弹底压力曲线的流场机理，解耦分析了其结构参数对压力冲击平滑效果的影响，并提出了次序优化的思路。数值结果表明:环形腔能有效阻挡燃气向上扩散且腔内具有存储氧气的功能，使二次燃烧沿时间维度展开，从而平滑弹底压力冲击；在由初容室空间几何约束确立环形腔布置高度和环形半径后，以长度作为调控弹底压力曲线的主要结构参数，收缩或扩张角度作为微调的结构参数，可使压力曲线逼近理想设计曲线；布置优化后的环形腔，加速度峰值减小9.26%，出筒速度减小4.13%，出筒时间延长2.5%。

关键词: 燃气弹射；压力冲击；环形腔；内弹道；流场；载荷