高温环境下线管式电极结构直流放电特性实验研究

Experimental Study on the DC Discharge Characteristics of Wire-to-cylinder Electrode Configuration at High Temperature

为了给等离子体技术在高温烟气净化的应用方面做些基础工作,研究了2种不同阴极材料在高温常压、异极距为5 mm的线管式放电装置中的直流放电特性,详细分析了环境温度对不同放电形式之间转化的影响。研究发现,室温下,随着负高压输出电压的增大,放电依次经历电晕和弧光2种放电形式。对于不锈钢电极,环境温度为350～650℃时,随着输出电压的增加,放电依次经历电晕、辉光和弧光3种放电形式;环境温度达到700℃后,放电只经历辉光和弧光2种放电形式。对于镧钨电极,在环境温度为350～850℃的区间内依次经历电晕、辉光和弧光放电3种放电形式。随着环境温度的升高,起晕电压和火花击穿电压同时降低,火花击穿电压的下降趋势更快,与阴极材料无关。

For applying plasma technologies in the purification of high-temperature flue gas in the future, we studied the DC discharge characteristics of two different cathodes at high temperatures and atmospheric pressure. In experiments, the cathode was installed in the wire-to-cylinder electrode pair with the heteropolar distance of 5 ram. The impact of ambient temperature on discharge forms was also analyzed in detail. The experimental results indicate that, with the increasing negative output voltage, the discharge on the electrode at room temperature sequentially shows two forms, namely, corona and arc. As for the stainless steel electrode with the increasing output voltage, when the ambient temperature changes from 350℃ to 650℃, the discharge sequentially goes through three forms, i.e. corona, glow, and arc, but only glow and arc are observed when the ambient temperature reaches 700℃. As for the La-W electrode, corona, glow, and arc are all observed at the ambient temperature of 350-850℃. As the ambient temperature increases, the corona onset voltage and the spark breakdown voltage both reduce, while the spark breakdown voltage will decrease faster and is nothing to do with the cathode material.