喷嘴对板介质阻挡放电特性的实验研究

Experimental Research on Characteristics of Nozzle-to-plate Dielectric Barrier Discharge

喷嘴对板介质阻挡放电是产生低温等离子体的有效方式,为了获得这种放电形式的放电特性,在实验室敞开的空气环境中,进行了"喷嘴-板"介质阻挡放电的初步理论研究。实验分别考察了等离子体放电通道的扩散角、放电伏安特性及电介质层位置对电流波形特性的影响几个方面。研究结果表明,扩散角随着电压的升高而增大,在相同电压条件下,喷嘴对板的极间距与扩散角呈反比关系,极间距愈小,扩散角愈大;伏安特性表明,外加电压达到放电临界电压之后,喷嘴数量越多电流越大,但不是单个喷嘴电流值的简单迭加;在相同的外加电压条件下,极间距越小,对应的电流值越大,并且随着外加电压的升高,较小的极间距的电流值增幅越大;此外,电介质层在两电极间的放置位置对放电特性产生影响,介质层在高压极与接地极之间时放电效果较好,过多靠近高压极或接地极效果较差。

Nozzle-to-plate dielectric barrier discharge is an effective method to generate non- thermal plasma. To obtain the characteristics of the discharge, this experiment was carried out in an open air environment in the laboratory. And the research mainly included several aspects, such as the diffuse angle of plasma channel, voltage - current characteristic as well as the effect of dielectric＇s position between the nozzle and the grounding plate on the characteristic of the current-waveform. The experimental results show that the diffuse angle tends to increase with the applied voltage. The electrode distances between the nozzle and the grounding plate is in inverse proportion to the diffuse angle under the same applied voltage conditions. The shorter electrode distances are, the larger diffuse angles will be. The results about voltage - current characteristic indicate that the more number of nozzles is, the larger electric currents when the applied voltage reached the discharge inception one are. Nevertheless, the current of the multinozzle is not equal to the simple sum of the single nozzle. Also the shorter electrode distances correspond to the larger increase range of currents with the applied voltage increasing. Furthermore, the discharge characteristic is related to the position of dielectric layer. When the dielectric layer is set at the middle between two electrodes, the better discharge effect can be attained than that when it is close to the nozzle or grounding plate.