Study on Ionic Wind of Bipolar Corona and Its Sterilization Effect

Plasma has shown excellent potential prospects in sterilization applications nowadays. In this paper, we firstly design a novel sterilizer based on bipolar corona discharge of needle-dielectric-needle configuration. With the help of the dielectric plate, the new sterilizer can effectively avoid spark or arc discharge and eventually converge into a neutral ionic wind. The electrical and optical characteristics of bipolar corona discharge were studied in detail, and the ionic wind velocity with different electrode spacings was measured. The results revealed that the average current had a quadratic relationship with the overvoltage following Townsend relation, and the ionic wind velocity was positively correlated with the overvoltage. Furthermore, we simply estimated the sterilization effect of bipolar corona discharge. It was found that the sterilization efficiency increases with the increase of exposure time, and decreases with the rise of distance from the grounded electrode to the petri dish. In particular, the bipolar corona has a satisfactory sterilization efficiency which can reach 100% at 6 minutes.