Soot particle re-entrainment in a corona discharge reactor

Among the various types of diesel after-treatment device, the corona discha rge reactor may be considered as a powerful tool for trapping submicron par ticles. But after precipitation on the electrodes occurs, the re-entrainmen t of particles is severe and often causes low or negative precipitation eff iciency. Experiments were performed to investigate the effect of an applied voltage on the re-entrainment of soot particles from the electrodes. A co- annular laminar diffusion flame burner was used as the soot generator. When a highly negative voltage was applied, exfoliation of the deposited soot p articles and an increase in concentration of particles smaller than approxi mately 150 nm were observed. Turbulence induced from the negative tuft coro na and sputtering caused particle re-entrainment from the corona wire and f rom plates as well. Under soot laden combustion gas, a streamer corona ofte n occurred in the wire-cylinder reactor. Because of its transient nature, s treamer corona violently increased the concentration of reentrained particl es and CO gas.