Transport Mechanism of Chemical Species in a Pin-water Atmospheric Discharge driven by Negative Voltage

Abstract

Atmospheric plasma discharges at a gas-liquid interface have recently paid great attention because of many possible applications. Although chemically reactive species, e.g., OH, O, O3, H2O2, play an important role in many applications, their transport mechanism has not yet been clarified. In this study, flow fields in air and water were observed to elucidate the mechanism of chemical species transport. We used a dielectric barrier discharge ignited between a metal pin electrode and the surface of water by applying high AC voltage of negative polarity to the metal pin electrode. To visualize the chemical species distribution in the water, methyl red solution was used and color change was observed. In addition, the relationship between the flow field and the color change of methyl red solution was examined. Furthermore, a computational study was conducted to understand the effect of the flow on the chemical species transport. The results show that the chemical species in the water were transported mainly by the circulating flow induced by the discharge.