Experimental and numerical analysis of streamers in pulsed corona and dielectric barrier discharges

Streamer characteristics have been experimentally and numerically analyzed for pulsed-corona discharge (PCD) and dielectric-barrier discharge (DBD) to find out how the discharge methods determine them and how they, in turn, affect the generation of radicals in flue gases. Experiments have been performed and compared for decomposition of a nitrogen oxide (NO) using PCD and DBD, and the electric field and average electron energy in the streamer are measured in each discharge by using line ratio of N₂⁺ to N₂^ß. The measured results of electron energy reasonably explain in terms of "G-value" how the measured NO removal efficiencies have come out. The PCD having high electron energy turns out to be more efficient for generating N radicals, whereas the DBD containing relatively low electron energy is more effective for producing O radicals. Three-dimensional (3-D) and one-dimensional (1-D) numerical simulations have been carried out to understand the observed streamer dynamics in both the PCD and DBD reactors. The 3-D numerical simulation has successfully illustrated the images of streamer front propagation in a wire-cylinder PCD reactor. In the 1-D simulation for the DBD, the recurrence phenomena of streamers have numerically appeared during the rising phase of an ac voltage. Furthermore, these numerical models have properly predicted the electric fields that are comparable with the corresponding average electron energies estimated from the emission spectral measurements for the PCD and DBD.