大气呼吸模式纳秒脉冲固体钕玻璃激光推进实验与数值模拟

Experimental and Numerical Study of Air-Breathing Mode Propulsion by Solid Nd:Glass Nanosecond Pulse Laser

采用1.06μm纳秒脉冲固体钕玻璃激光器和K9玻璃材质铃形推进器开展了大气呼吸模式单脉冲竖直激光推进实验和相应的数值模拟研究。结果表明,纳秒脉冲激光推进中焦距在推进器构型因素中占主导地位,焦距越大,推进性能越好,焦距相同时,开口张角小、喷管长的推进器获得的冲量耦合系数越大,这与微秒脉冲CO2激光推进的结论不同。分析认为超短脉冲对推进器壁面的热损伤是短焦距推进器性能较差的真正原因。在18 J单脉冲激光作用下,12.5 g推进器被竖直推进24.5 mm,冲量耦合系数达到478.75μN.s.J-1。通过与CO2激光推进实验结果比较分析发现,纳秒脉冲激光的单脉冲推进效果要优于微秒脉冲激光。

With a 1.06 μm solid Nd：glass nanosecond pulse laser and a bell-shaped thruster made of K9 glass,both vertical single-pulse propulsion experiment and the corresponding numerical simulation are studied.The results show that,the focal length dominates among the structural factors of thruster in the propulsion by nanosecond pulse laser.The larger focal length corresponds to a better propulsion performance,and at the same focal length,the thruster with smaller open angle and longer scale can achieve higher impulse coupling coefficient,which are different from the results achieved in the propulsion by a microsecond pulse CO2 laser.It is believed that the reason for the poor performance of thruster with shorter focal length is the thermal damage of thruster caused by ultrashort pulse laser.The 12.5 g thruster is vertically propelled for a height of 24.5 mm by a 18 J single pulse laser,and its impulse coupling coefficient is 478.75 μN·s·J^-1.By comparing with the experimental results based on the CO2 laser,the nanosecond pulse laser is better than the microsecond pulse laser in the single pulse propulsion.