Effect of Non-thermal Plasma on Flame

J. B. Lee, J. Hwang

Research output: Contribution to journalConference articlepeer-review

1 Citation (Scopus)


Effect of non-thermal plasma on flame was experimentally investigated with a sooting C2H4 diffusion flame. The start of this study is based on the reduction of particulate materials (PM) emitted from diesel car. The particulate materials are very harmful when the human inhaled, because of its small size. They can damage and hurt the human lung cells. Some part of PM can be conditionally removed by catalyst. But the soot particles, which are generated in high temperature region in flame are not easily removed by catalyst. In these days, the applications of plasma for diesel car emission are vigorously studied in related company. A pin-to-pin electrode was set up to generate non-thermal plasma across the flame. One electrode was connected to DC (positive or negative) or AC power supply, and the other was grounded. With increasing the applied voltage, the flame width increased but the flame length decreased, which was due to the electric field induced ionic wind and the electrostatic repulsion between the unipolarly charged soot particles. The results of particle measurements show that the corona discharge tended to prohibit agglomeration between unipolarly charged particles, increase the specific area of the particles and the chances of being oxidized, and also enhance oxidation by aeration caused by the corona induced ionic wind. This aeration could reduce surface growth rate of primary particles and also alter combustion characteristics by enhancing the mixing of entrained air with fuel. With the applied voltages below ±5.5 kV, the size of soot agglomerates and their overall number concentration decreased for both cases of positive and negative coronas. However, as the applied voltage increased above ±5.5 kV, the concentration of nano particles smaller than 100 nm increased especially in the case of negative corona. This might be caused by in-agglomeration due to strong electrostatic repulsion, in conjunction with the flame instability, which often occurs when the ionic wind blows off the flame tip to be split into several ones or to be fluttered in violence. The effect of AC corona on size and number concentration of soot agglomerates emitted from the flame was compared with that of DC corona for the same electrical current. The results show that the reduction of soot emission was less effective for AC corona than DC corona for the experimental conditions selected.

Original languageEnglish
Pages (from-to)151
Number of pages1
JournalIEEE International Conference on Plasma Science
Publication statusPublished - 2003
Event2003 IEEE International Conference on Plasma Science - Jeju, Korea, Republic of
Duration: 2003 Jun 22003 Jun 5

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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