脉冲等离子射流在液体介质中扩展特性的测量与分析

为了深入了解液体工质电热化学炮的燃烧推进机理,设计了模拟实验装置。采用高速录像系统,观察了脉冲等离子射流喷入液体介质中的扩展过程。测量了脉冲等离子射流在液体介质中形成Taylor空腔的轴向位移和体积变化。得到了Taylor空腔体积随时间变化的定量扩展规律。讨论了贮液室边界形状、放电电压和喷嘴直径对等离子射流扩展的影响。结果表明,两相交界处由于湍流掺混形成皱褶不光滑的交界面。Taylor空腔扩展过程中出现了明显的振荡现象。渐扩结构因子由0.6减小到0.4,轴向位移第一峰值和体积第一峰值分别增大16.6%和12.4%。放电电压由3000 V减小到2100 V,轴向位移第一峰值和体积第一峰值分别减小36.1%和60.7%。喷嘴直径由2 mm减小到1.5 mm,轴向位移第一峰值和体积第一峰值分别减小27.2%和56.7%。

Measurement and Analysis of Expansion Characteristics of Pulsed Plasma Jet in Liquid Medium

To deeply understand the combustion and propulsion mechanism in liquid propellant electrothermal chemical gun, an experiment device was designed.The expansion process of injecting the pulsed plasma jet into the liquid medium was observed by a high-speed video system. The changes in axial displacement and volume of Taylor cavity formed by the interaction of plasma jet and liquid medium were measured. The quantitative expansion law for the change in Taylor cavity volume with time was obtained. The effects of liquid chamber boundary shape, discharge voltage and nozzle diameter on the pulsed plasma jet expansion were discussed . Results show that the non smooth intefacer with wrinkles in junction of two-phase due to the turbulent mixing is formed. There is an obvious oscillation phenomenon in the expansion process of Taylor cavity. The stepped-wall structure factor decreases from 0.6 to 0.4, the axial displacement first peak and the volume first peak increase by 16.6% and 12.4%, respectively. The discharge voltage decreases from 3000 V to 2100 V, the axial displacement first peak and the volume first peak reduce by 36.1% and 60.7%, respectively. The nozzle diameter decreases from 2 mm to 1.5 mm, the axial displacement first peak and the volume first peak reduce by 27.2% and 56.7% , respectively.