为研究喷管喉部半径变化对燃气弹射载荷和内弹道性能的影响,建立了含二次燃烧和尾罩运动的二维轴对称数值模型。在验证数值模型可靠的基础上,研究了喷管喉部半径变化导致流场结构和二次燃烧核心区域改变的机理。结果表明:随着喷管喉部半径的增大,发生二次燃烧的时间相对提前,核心燃烧区域由发射筒底部逐渐上移;燃气单位时间内进入量的增加,导致监测点压力峰值增加,峰值所在时刻提前;在实验装置的基础上,当喉部半径扩大了1.05倍时,加速度峰值增大了5.4%,出筒时间缩短了2.7%,出筒速度增大了10.8%,且载荷与温度变化最为平稳,为最优内弹道设计方案。

The two-dimensional axisymmetric numerical flow model with secondary combustion and trail cover moving boundary was established to study the influence of nozzle radius change on gas ejection load and internal ballistic performance. On the basis of verifying the reliability of the numerical model, the mechanism of the change of the nozzle throat radius and the change of the flow field structure and the secondary combustion core region was studied. The results show that with the increase of the radius of the nozzle throat, the time of secondary combustion is relatively advanced, and the core combustion area is gradually moved upward from the bottom of the launching tube; the increase of the amount of gas per unit time increases the peak value of the monitoring point. The peak time is advanced; Based on the experimental setup, when the throat radius is increased by 1.05 times, the acceleration peak is increased by 5.4%, the discharge time is shortened by 2.7%, the discharge speed is increased by 10.8%, and the load and temperature changes are the most stable, which is the optimal Design of internal ballistics。