用于PJMIF的超快气阀性能表征
Performance Characterization of an Ultrafast Gas Valve for PJMIF

上海科技大学正在研发第三代用于PJMIF的同轴等离子体枪STG1以及配套超快气阀。STG1的超快气阀需要在百微秒(~100 μs)的开关时间内注入0~30 mg的均匀气体。超快气阀利用j × B电磁力驱动金属飞盘控制气路开关，检测气阀结构中金属飞盘弹射时的运动轨迹可以直接体现气阀的稳定性和开关性能。针对两种结构的超快气阀搭建实验平台，采用激光三角测距法对气阀的金属飞盘的位移进行检测，获得金属飞盘在两种结构下的位移曲线，以及新型结构的气阀在不同电压下的开关时间，并通过有限元分析法对飞盘弹射过程中的振动现象进行验证。研究结果表明，金属飞盘在弹射过程中会产生中心振动，新型弹簧和短翼无孔飞盘组合下的新型结构相比于传统结构具有更高的重复性，可以通过改变电压的方式可以有效的将气阀的开关时间控制在0~300 μs。
The coaxial plasma gun used for PJMIF requires the injection of 0~30 mg of uniform gas with the ultrafast gas valve at the switching time of hundreds of microseconds (~300 μs). The stability and switching time of the ultrafast gas valve can be directly determined by measuring the position displacement trajectory of the metal flyer plate ejection. An experimental platform was built for detecting two kinds of ultrafast gas valves, and the displacement of metal flyer plate of the valve was detected by laser triangulation method. The displacement curves of the metal flyer plate under two kinds of structures and the switching time of the gas valve of the new structure under different voltages were obtained. The oscillation phenomenon during the flyer plate ejection process was verified by finite element analysis. The results show that the metal flyer plate will produce the central oscillation during the ejection process. Compared with the traditional structure, the new structure under the combination of new spring and short wing flyer plate has higher repeatability, and can effectively control the switching time of the gas valve within 0~300 μs by changing the voltage.