Planar Laser-Induced Fluorescence Diagnostics for Spatiotemporal OH Evolution in Pulsed Corona Discharge

OH radicals play an important role in pollutant removal in nonthermal plasmas. It is crucial to clarify the behavior of OH radicals in this process. A time-resolved 2-D OH radial distribution was investigated in a pulsed corona discharge by planar laser-induced fluorescence at atmospheric pressure and room temperature. The OH evolutions under different gas components were studied, and the evolution process was simulated. The OH decay processes were found to be divided into two periods: a fast decay period and a slow decay period. The O, N, and HO₂ are dominant radicals for OH generation and decay. The OH radicals are mainly generated near a nozzle electrode. The concentration variations of O₂, NO, and H₂O in the background gas led to different OH density evolutions. The OH distribution zones were different as gas components varied. The maximum area of OH radical distribution after discharge decreased by 20% as O₂ increased from 5% to 8 %, and it decreased by 69% as NO (150 ppm) was added into the background gas.