Fundamental Investigation of Streamer Discharges in Coaxial Reactor for NOx Treatment Using Nanosecond Pulsed Power

The appearance of streamer discharge in the coaxial electrode was studied using nanosecond pulse power. It is important to investigate the characteristics of the streamer discharge in the coaxial electrode in order to improve the performance of the nitrogen oxide treatment. The dependence of the streamer discharge on the electric field strength at the inner electrode and the tail of the pulse was investigated by using the simulated electrode as a reactor. The number of streamers increased with the electric field strength on the inner-electrode surface by changing the charging voltage. On the other hand, under these experimental conditions, the number of streamers little changed by changing the diameter of the inner electrode. An experiment excluding tail of pulse, to suppress the occurrence of secondary streamers, was conducted. Only primary streamer discharges were generated and the developing length of the primary streamer was related to the electric field strength on the surface of the inner electrode. In the development of coaxial reactors for gas treatment using nanosecond pulsed power, the reactor electrode should be designed so as to utilize the primary streamer discharge. The selection of a thin inner electrode leads to the concentration of streamer discharges near the internal electrode, and the thin external electrode utilizes the streamer concentration.