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.