Abstract: Mechanism of surface cavitation produced by laser-generated ablation was analyzed.Photos of flow field was obtained by high-speed camera.It was found that development speed of cavitation was very high during the first 100 μs,and it would be in a relative equilibrium state in the next several hundreds microseconds.A simple model was used to calculate the balance shape of cavitation in different energy-flux density and its limitation was presented.Results of this study is valuable for discovering formation mechanics of thrust in the process of laser induced ablation of water and development of laser propulsion with liquid propellants.

Key words: Laser propulsion;Water ablation;Cavitation;Thrust

摘要： 分析了激光烧蚀液体时形成表面空穴的机理。利用高速相机获得CO2激光烧蚀蒸馏水的流场照片,对空穴的发展过程进行了分析,发现空穴的快速发展期在最初的100μs内,之后在几百μs内保持平衡。用简单模型计算了不同能流密度下,空穴平衡时的形状,并分析了模型的局限性。研究结果对于揭示激光烧蚀水产生推力的机理有重要意义,有利于促进水工质激光推进的发展。

关键词: 激光推进;水烧蚀;空穴;推力