组合喷管构形激光推力器推进性能数值研究

Numerical Study on Propulsion Performance of Laser Thruster with Combined Nozzle Shape

激光推力器中,单一构形如旋转抛物形、锥形的喷管设计未对高压流场实现有效约束,推进性能较低。通过建立的计算模型,针对吸气模式下,抛物形与圆柱形喷管组合的激光推力器模型进行了数值研究,围绕圆柱喷管长度与脉宽对推进性能的影响规律以及流场演化特征进行了分析。结果显示：冲量耦合系数随圆柱喷管的增长而增加并趋于恒定,直径20mm、圆柱喷管长80mm的推力器模型在单脉冲激光能量密度1.5J/cm^2的条件下获得的冲量耦合系数高达627.7N/MW;脉宽对冲量耦合系数也有一定影响。

Laser thrusters with single nozzle like parabolic or conical failed to constrict the flow field of high pressure effectively,resulting in poor propulsive performance.Under the condition of air-breathing mode,through building physical computation model,a thruster model with nozzle combined by parabolic and cylindrical shape is studied numerically,then the influences of the cylindrical length and pulse width on propulsion performance and the evolution process of flow field are analyzed.The results show that momentum coupling coefficient increased with cylindrical length and approached constant,a thruster model of diameter 20 mm and cylindrical length 80 mm obtains 627.7 N/MW at single pulse energy density 1.5 J/cm^2,and pulse width also affects momentum coupling coefficient at certain extent.