微尺度下激光烧蚀含能薄膜材料的微推进机理研究

The dynamic coupling of energetic propellants chemical energy and laser energy can result in a substantial increase of specific impulse for solid propellant .Base on this principle, the laser micro-propulsion technology for satellite will be very competitive in the future. However, the reaction takes place in micro-scale, and not only the volume of plume is very few, but also has very complex composition. It is so difficult to quantitatively discriminate how many propellants were ionized, how many were ablated, and how many were ejected without reaction, which result in the dynamic coupling process of chemical and laser energy and the transforming mechanism of energy to thrust cannot be deeply studied. This study intends to carry out a transient detection to sufficient plume product generated by a high-frequency micro laser propulsion thruster, test the ratio of the ionization and chemical energy, and trace and inverse the possible chemical reaction process. Then the propellants’ composition will be adjusted according the experiment results for better performance. An integrated test platform is established to have an real-time detection for plume product and thruster performance. Additionally the discrete element method is used here to simulate the total process in micro-scale. Finally, based on the study of mechanism experiment and numerical simulation, a new set of research methods for laser micro-propulsion is expected to be established.

较低功率密度激光烧蚀含能工质薄膜产生的化学能释放与激光能量的耦合可大幅提高推进比冲，是未来具备竞争力的空间微推进技术。但是，由于整个过程发生在微尺度层面，羽流产物极其微少，成分极其复杂，究竟有多少工质被电离？有多少工质被烧蚀？被烧蚀的工质中又有多少发生了化学反应？有多少未反应就被喷出？都难以定量分析，导致对激光烧蚀工质的化学能释放与激光能量的动态耦合过程和推力转化机理的研究难以深入。本研究拟对高频激光推力器产生的足量羽流开展瞬态检测，定量分析电离能和化学能的占比关系，追踪和反演化学反应过程，并根据实验结果调整工质配比，提高推进性能，从而构建起工质配比、羽流产物与推进性能相迭代的机理实验研究框架；引入离散元方法开展数值仿真，结合机理实验参数，引入化学反应，对产物不同的工质区细化分区开展研究。最终建立一套从机理实验到数值仿真的激光微推进研究体系。

为研究微尺度下激光烧蚀含能薄膜材料的微推进机理研究，调研了激光微推进与含能材料的反应机理，开展含能工质配置工作。针对含能工质特点，对激光烧蚀含能工质进行匹配研究，初步筛选出含能工质：GAP工质。由于GAP工质是负氧材料，设计了一种添加氧化剂的GAP复合工质。研制了高真空环境下冲量扭摆仪，并对GAP工质和掺杂氧化剂的GAP复合工质在不同激光参数下进行了性能测试。利用瞬态发射光谱法对激光烧蚀GAP工质的瞬态产物进行了分析。基于实验研究和理论分析，完善了离散元模拟方法，引入化学反应释放的化学能，揭示了微射流形成的细观机理，并对激光功率、工质厚度的影响进行了模拟研究，并反向指导设计，形成研究闭环。