点火形状对激光推力器推进性能的影响

Influence of Ignition Shape on Propulsion Performance of Laser Thruster

在单脉冲激光能量为70 J作用下,用数值计算方法,对点火形状沿抛物形喷管对称轴的变化及其对激光推力器推进性能的影响进行了研究。研究表明,对于内表面母线方程y^2=20x,开口直径为0.08 m的喷管,当点火位置距离喷管内壁顶点0.02 m,点火区体积不变时,椭球或圆柱点火形状的变化对冲量耦合系数的影响很小;点火形状沿水平方向越细长,推力的变化幅度越小。通过分析点火形状对推进性能的影响,为设计聚焦系统提供了参考依据。

The influence on the change of ignition shape along the symmetry axis of the parabolic nozzle on propulsion performance of laser thruster is studied, using computational fluid dynamics pro- gramme with the action of 70 J single pulse laser. The results suggest that for the nozzle with the generatrix equation of the inner surface being y^2 =20x and the exit diameter being 0.08 m, the influence of ignition shape on impulse coupling coefficient is less for the different shape of the ellipsoid or column ignition area, when the ignition position is 0.02 m far from the apex of the nozzle＇s inner wall and its volume is unchangeable. However, the ignition area is slenderer along the horizontal direction, the amplitude of the thrust＇s change is smaller. It provides reference for the choice of designing focusing system by analyzing the influence of ignition shape on propulsion performance.