边界形状影响等离子体射流扩展特性的实验研究

为了探索燃烧室边界形状在控制燃烧稳定性方面的特性，设计了圆柱型和圆柱渐扩型充液室，运用高速录像系统研究了等离子体射流在充液室中的扩展过程。结果表明：等离子体射流在液体工质中扩展时，等离子体一液体两相流体速度差较大，TaylorHelmh01tz不稳定效应强烈，圆柱型充液室中，Taylor空腔界面自由，界面增长随机脉动性较大；渐扩型充液室能够使两相流边界受到约束，使Taylor空腔沿着充液室边界逐级扩展，从而减弱了Taylor-Helmholtz不稳定效应，有效抑制了界面增长的随机脉动性。放电电压、喷嘴直径和渐扩结构因子△D／L对Taylor空腔扩展过程均有不同程度的影响，通过对这些参数的优化匹配，可以在一定程度上实现对射流扩展过程的控制。

Experimental study on boundary shape affecting propagation properties of plasma jet

In order to explore the influences of the chamber boundary shape on the combustion instability, cylindrical and stepped-wall chambers were designed, and the fast frame digital cam- era system was applied to study the plasma jet propagation in the liquid. The results indicate that when the plasma jet propagates in liquid, the velocity difference between the plasma and liquid is very large, which makes the Taylor-Helmholtz instability effect very strong. In cylindrical cham- ber, the interfaee of Taylor cavity is unconstrained and the increase of the interfaee area is of much random fluctuation. The stepped-wall chamber can make the Taylor cavity propagate along the stepped-wall boundary, which constrains the two phase fluids＇ interface. So that the Taylor- Helmholtz instability effect is weakened and the random fluctuation of the increase of the inter- faee area is limited effectively. The parameters such as discharge voltage, nozzle diameter and stepped-wall structure factor （AD/L） have effects on the Taylor eavity＇s propagation. The process of the plasma jet propagation in the liquid can be controlled by optimizing these parameters.