激光脉冲波形对推力器性能的影响

激光推力器性能优化是激光推力器研究的重要组成部分。受硬件条件的限制,激光推进领域激光脉冲时间波形对推力器性能影响的研究并未广泛展开。以两台CO2激光器的实际脉冲波形为基准,建立了两组激光能量输入模型,其波形时间分布相似,单脉冲能量相同,但脉冲持续时间及峰值功率不同。数值计算比较了不同脉冲波形下抛物型激光推力器的性能,结果表明:峰值功率和脉冲持续时间是影响推力器性能的重要参数,高功率短持续时间的脉冲波形更有利于提高冲量耦合系数和推力;两种实际脉冲波形的冲量耦合系数数值计算结果分别为40.9×10-5N.s/J,30.0×10-5N.s/J,与文献报道实验测量结果基本吻合。为激光推进CO2激光器的脉冲波形设计提供支持及研究思路,具有一定参考价值。

Effects of Laser Pulse Waveform on Lightcraft Performance

Performance optimization is one of important facets for the investigation of laser thruster. Due to the limitation of hardware, effects of laser pulse waveform on lightcraft performance have not been carried out widely in the field of laser propulsion. Based on actual pulse waveform of two CO2 lasers, two groups of energy injecting models are formed, whose temporal waveforms are similar, single pulse energies are the same, but peak powers and pulse durations are different. Performances of parabolic laser thruster obtained by numerical calculations are compared under the conditions of different pulse waveforms. The results indicate that peak power and pulse duration are important parameters in determining the lightcraft performance and waveform with shorter duration and higher peak power is more efficient in improving impulse coupling coefficient and force. The numerical results of impulse coupling coefficient with two actual pulse waveforms are 40.9×10-5 N·s/J and 30.0×10-5 N·s/J respectively, which are consistent with experimental ones reported by other literatures. The presented method and investigative idea can be used in pulse waveform design of CO2 laser and provide some reference for laser propulsion research.