Time-Resolved PLIF Imaging of OH Radicals in the Afterglow of Nanosecond Pulsed Discharge in Combustible Mixtures

A time-resolved planar laser-induced fluorescence (PLIF) imaging technique has been used to investigate the spatial distribution of OH radical dynamics in the afterglow of a pulsed nanosecond discharge. Experiments were carried out using a lean methane/air mixture, at temperatures of 300 K and 500 K and at atmospheric pressure. The nanosecond pulsed discharge was formed in a pin-to-pin electrode system. Time-resolved PLIF imaging indicated uniform OH radical dynamics along the discharge channel. Comparison of OH radical emission dynamics with discharge emission dynamics from excited nitrogen revealed a close similarity in spatial distribution and allowed to clarify the mechanisms of atomic oxygen formation.