烧蚀模式激光推进的实验研究

采用CO2激光器和固体推进剂对三种构形的抛物型激光推力器模型进行了烧蚀模式下的单脉冲、多脉冲连续推进的对比实验,单脉冲实验获得的最高冲量耦合系数达到2.7×10-4N/W,对多脉冲连续推进时的冲量耦合系数有较大幅度的下降进行了分析,尝试采用PVDF薄膜传感器,测量了推力器内壁的瞬态压强,并采用热像仪对推力器的外壁温升进行了连续记录,为进一步研究激光能量转化为推力的机理以及热力冲击的影响提供了直接的数据。

Experimental investigation on ablation mode of laser propulsion

With a high power TEA-CO2 pulsed laser(20 J/pulse,66~150 Hz),both single-and multi-pulse propulsion experiments are conducted for three kinds of parabolic thrusters with 3 solid propellants POM,PMMA and PVC,respectively.The single pulse experiments give the maximum momentum coupling coefficient Cm 2.7×10-4 N/W(thruster A with POM).The Cm for multi pulse experiments is much lower than the single pulse case.The PVDF stress gauges and infrared camera are used to measure the pressure and temperature distribution and evolution on the wall of the thrusters.The maximum temperature increase for 49 pulses and peak pressure measured are 110 ℃ and 2.3 MPa,respectively.It suggests the thermo-mechanical impact effect should be taken into account in the laser thruster study.