大气压层流等离子体射流特性及其用于材料表面处理的效果

在大气压条件下产生出能量衰减慢且分布均匀、噪音小的氩和氮氩混合气的层流等离子体射流。与湍流等离子体射流相比，由于对周围冷气体卷吸减少，层流射流在喷射方向的长度可增长６倍。试验表明，只有采用结构合理的等离子枪，综合调控供气和电参数条件，抑制气流的脉动和抖动，才能形成层流等离子体射流。结合数值计算对等离了体气流温度分布的定性分析，说明层流情况下射流径向能量分布集中，轴向温度变化平缓，有利于材料表面处理

Characteristics of Laminar-flow Plasma Jet at Atmospheric Pressure and Its Effectiveness Used for Material Surface Treatment

Laminar-flow plasma jet of favorable energy distribution and very low noise could be generated at atmospheric pressure with argon or a mixture of argon and nitrogen as the working gases.The laminar plasma jet showed a length of about 7 times than that of a turbulent one,because of the reduced air entrainment.Experimental results confirmed that the laminar plasma jet could only be generated by suppressing the flow surging and whipping with a reasonable torch structure under a set of well balanced gas feeding and power conditions.Simulated temperature distribution of plasma jet indicated that a laminar plasma jet has a relatively centralized energy distribution in its radial direction and greatly reduced temperature gradient in the axial direction.This could be favorable for the control of treatment temperature,region and stress conditions of material when the laminar jet is used for materials surface processing.