脉冲重复频率对微秒脉冲滑动放电特性影响的实验研究

Experimental Study on the Effect of the Pulse Repetition Frequency on the Characteristics of Microsecond-Pulse Gliding Discharges

脉冲滑动放电能够在大气压下产生高能量、高电子密度的低温等离子体，在废水处理、点火助燃、甲炕转化等领域具有广泛的应用前景。为了研究重复频率微秒脉冲电源对滑动放电特性的影响，采用自主研制的重复频率微秒脉冲电源，通过改变电源的脉冲重复频率进行了实验研究。结果表明在大气压空气中滑动放电产生的火花通道能够顺着气流的方向沿刀型电极刃面向上滑动，最大高度和长度可以达到29mm和43mm，各火花通道彼此分散。进一步分析脉冲重复频率对滑动放电的影响规律可知，高频时（500-1500Hz），随着脉冲重复频率的增大，火花放电通道逐渐向上发展，发生火花放电的最高位置逐渐向刀型电极的27尖处靠拢。滑动放电的击穿电压逐渐减小，工作电压逐渐分散。这与驻留粒子的记忆效应和电极间隙的变化有关。低频时（1～300Hz），由于气流的作用，电极间隙内驻留的粒子较少，其记忆效应对滑动放电的影响较弱，火花通道不能沿刀型电极刃面向上滑动。

Pulsed gliding discharges can generate non-thermal plasmas with high-energy and high electron density at atmospheric pressure, which have widely application prospects in the fields of effluent treatment, ignition and combustion, and methane conversion. In this paper, in order to investigate the characteristics of the microsecond- pulse gliding discharges, experimental studies of the gliding discharges at different pulse repetition frequencies （PRFs） are carried out by using a lab-made microsecond-pulse generator. The experimental results show that spark channels moved along the blade of the sword electrodes in a fast air flow and in the flow direction at atmospheric pressure. The highest altitude of the spark channel reaches 29 mm and the longest length of the spark channel is 43 mm. Moreover, the spark channels dispersed with each other. Furthermore, the results of the effect of the PRF on the characteristics of microsecond-pulse gliding discharges show that, in the case of high PRF （500 - 1 500 Hz）, the spark channels gradually moves upwards with the increase of the PRF, and the highest altitude of the spark channel moves towards the tool nose. As the PRF increased, the breakdown voltage is decreased and the working voltage is dispersed. Such variation is closely related to the memory effect of the residual particles and the change of the electrode distance. In the case of low PRF （1 -300 Hz）, because the memory effect of the residual particles has less effect on the gliding discharges in air flow, spark channels cannot move upwards along the blade of the sword electrodes.