空气条件下介质阻挡放电影响因素的研究

Study on Influential Factors of Dielectric Barrier Discharge in Air

为了解决低气压等离子体用于工业生产时存在真空系统昂贵和难以实现试品的批量处理等缺点,采用环氧树脂和聚四氟乙烯(PTFE)作为介质阻挡放电(DBD)的阻挡介质,探讨了在不同放电间距d(2-5 mm)、气压p(10-100 kPa)和外施电压U下的放电特性。结果表明,PTFE为阻挡介质,d≤3 mm时,在大气压下可利用DBD的形式产生辉光放电,当d>4 mm时,则不能得到稳定的DBD;在不同气压下,DBD稳定放电对应的电压区间范围在d为3 mm时最大;次大气压下辉光放电的特征较大气压下更明显,辉光放电更易获得,稳定放电的电压区间也更大。

It is difficult for low pressure plasma to meet the requirements of industry application for batch processing of work pieces. The dielectric barrier discharge （DBD） in air is tried to generate the atmospheric and sub-atmospheric pressurized glow discharge （ APGD＆SAPGD） Epoxy and polytetrafluoroethylene（PTFE）are employed as the dielectric barrier, respectively. The gap spacing is exactly selected as 2, 3, 4 or 5 mm by a vernier electrode system. A two-grade power supply with two transformers is utilized to obtain a precise voltage output adjustment of 100 V. With the high voltage divider, the sampling resistance and capacitor, the discharge voltage, current and power can be measured. Based on the discharge Lissagous figures, the equivalent capacitance of gas gap and dielectric material can be calculated. The influences of different barrier materials （ epoxy and PTFE）, electrode spacing （ 2-5 mm）, air pressure （ 10-100 kPa） and amplitude of applied voltage on DBD discharge phenomena are discussed in detail When the gap distance is not wider than 3 mm, it seems easy to generate homogeneous and stable APGD by DBD with 0. 5 mm thick PTFE. With the electrode spacing increasing, the voltage range of maintaining stable glow dis- charge reduces, and when the gap is beyond 4 mm, it is difficult to achieve a stable DBD. Under different pressures, the voltage range of maintaining stable DBD is the largest for a gap distance of 3 mm. Compared with 100 kPa discharge, it is easier to achieve a SAPGD, which also has a wider stable discharge voltage range.