层流等离子体发生器设计关键技术研究之大尺度分流现象

Study on the Key Design Technology of the Laminar Plasma Torch:Large Scale Shunting Phenomenon

分析等离子体发生器工作过程中大尺度分流现象产生机理,明确大尺度分流现象产生条件,从而提出相应的抑制措施:(1)增大电弧与阳极壁面的击穿电压,使击穿电压分布曲线上移;(2)限制阳极弧根在Z轴的最大运动范围,使电弧沿轴线的电势分布始终不满足产生大尺度分流的条件;(3)限制阳极壁面在Z轴方向的带电长度,缩小击穿电压分布曲线作用范围,并在其作用范围内不能满足产生大尺度分流的条件。基于对抑制措施的探讨,从避免大尺度分流现象产生角度,提出层流等离子体发生器结构设计要点:采用分段式阳极结构,这不仅可以避免大尺度分流现象的产生,提高层流等离子体射流稳定性,而且可以通过改变中间电极数量来实现在相同工作参数下调整层流等离子体发生器工作功率范围,并有利于提高大功率层流等离子体发生器电极的使用寿命。

The mechanism of large-scale shunt phenomenon is analyzed to specify its generation conditions. Based on the analysis,the measures of suppressing the large-scale shunt phenomenon are proposed and analysed:( 1) increase the breakdown voltage between the plasma arc and the inner wall of the anode to move upper the distribution curve of the breakdown voltage;( 2) limiting the motion range of the anode attachment at the axial direction of anode to make sure that the electric potential distribution of the plasma arc can’t meet the demands to generate large scale shunting phenomenon;( 3) limiting the length of the anode to reduce the effective scope of the breakdown voltage distribution carve and make sure that the corresponding electric potential distribution of plasma arc can’t meet the demands to generate large scale shunting phenomenon.Lastly,based on the analysis of the measures,the key point for designing the laminar plasma torch is proposed in the perspective of suppressing the large scale shunting: adopting segmented anode structure to design laminar plasma torch,which not only could suppress the generation of the large scale shunting to improve the stability of the laminar plasma jet,but also could adjust the working power of the laminar plasma torch with same working conditions by increasing or reducing the number of inter-electrodes,and improve the service life of laminar plasma torch.