基于Laval喷管的滑动电弧放电等离子体发生器及其工作特性分析

为了研究产生于Laval喷管中的一种新型滑动电弧放电的物理特性,研究了不同流量工作气体(空气)条件下产生的等离子体电弧的伏安特性,并利用高速摄影仪对此种新型等离子体的滑动电弧发展过程进行了跟踪,记录了滑动电弧等离子体击穿—延长—电弧最大—熄灭的循环过程。结果表明:随着工作气体流量的增加,电极电压波形出现突变的频率越来越高;电流波形随着气体流量的增加除了击穿时突变点增多外大致形状不变,近似于正弦波形,且最大值都为0.4A;半周期内的平均电压在629～1 347V范围内变化。分析得出,流量变化对这种滑动电弧放电的伏安特性,特别是电压特性存在剧烈影响,这一点也可以从高速摄影所得图像中看出。

Gliding Arc Plasma Generator Based on Laval Nozzle and Its Characteristics

In order to study the physical characteristics of a new type of gliding arc discharge plasma generated in a Laval nozzle,we studied its voltage-ampere(V-A) characteristics and movement under various flow rates of working gas(air).In order to analyze the developing process of the gliding arc discharge plasma,we applied high-speed photographic apparatus to track and record the physical cycles of "gliding arc breaking down—lengthening—the largest arc lengthening—extinguishing".The results show that frequency of mutations of the electrode voltage waveform becomes much higher with the increasing flow rate of working gas.Waveform of the current is generally stable which is similar to sine waveform,except that current mutations increase with the increasing flow rate in the breakdown condition.The maximum value of sine waveform is 0.4 A.The average voltage in half a cycle is from 629 to1347 V,and its changing trend is like the power capacity.It can be seen from the analysis that changing of flow rate influences the V-A characteristics severely,especially the voltage characteristics,and this can also be seen from the Voltage-Ampere obtained by the high-speed photographic instrument.