Study on influential factors of dielectric barrier discharge in air

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 discharge 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.