亚声速来流对吸气式纳秒激光推进性能的影响

Effects of Subsonic Inflow on Performance of Air-Breathing Nanosecond Laser Propulsion

关键词:  激光推进  吸气式  纳秒激光  亚声速来流  冲量耦合系数 

Key words:  Laser propulsion  Air-breathing mode  Nanosecond laser  Subsonic inflow  Impulse coupling coefficient

摘要:

针对亚声速来流条件下吸气式纳秒激光推进的机理,通过Fluent流体仿真软件,数值模拟不同来流马赫数条件下推进器内外流场的演化过程,分析来流速度对推进性能的影响。结果表明:低速条件下,空气来流强度小,对推进器和激光冲击波的影响较小,冲击波近似自由向外传播,与推进器作用较为充分,使得冲量耦合系数较高；随着亚声速来流的增大,自由空气来流强度增大,推进器所受阻力增大,并抑制冲击波自由传播,加速冲击波耗散,缩短冲击波的有效做功时间,导致冲量耦合系数快速下降。 

Abstract:

Aimed at understanding the mechanism of air-breathing nanosecond laser propulsion in subsonic inflow, with the software Fluent, the flow field in different subsonic inflow was numerically simulated. The effects of subsonic inflow on the performance of air-breathing nanosecond laser propulsion were analyzed. The simulation results show that the impulse coupling coefficient decreases rapidly with the increase of subsonic inflow Mach number. In low subsonic inflow, the thruster and shock wave are relatively less influenced and the propagation of shock wave is similar to the situation of no inflow. With the increase of subsonic inflow Mach number, the air drag increases significantly, and the blowing process of shock wave to the downstream is accelerated, therefore the time of interaction between the shock wave and the thruster is shortened, which ultimately lead to the rapid decrease of the impulse coupling coefficient. 