中文摘要：

等离子喷枪内电弧形成及其等离子火焰的结构和特性对等离子喷涂涂层的质量有重要的影响。本文研究阴极形状对等离子弧和射流火焰的影响，采用数值模拟方法，对等离子喷枪内的流动与换热进行三维稳态模拟。三种阴极形状等离子喷枪的模拟结果显示，与圆锥形阴极尖端相比，圆弧形阴极尖端对应的等离子弧长拉长，等离子射流火焰在喷嘴出口处温度降低、速度减小、温度场和速度场的轴对称性增强，速度场的扰动减小。

英文摘要：

Plasma generation and plasma jet flame structure have critical impact on coating properties in plasma spraying process. This paper is to study the effects of cathode shape on plasma arc and plasma jet using numerical approach. Three dimensional simulations were performed for plasma flow and heat transfer inside plasma spray gun with three types of cathode tip shape. The results revealed that the torch with arc-shaped cathode tip is of characteristics such as longer arc length, higher temperature and larger velocity at the nozzle exit, as well as increased axial symmetry and reduced fluctuation in velocity along the central axis.