An analysis of pulsed streamer discharge using a high-speed camera

Pulsed streamer discharges have been extensively used in many applications such as control of NO/sub x/ and SO/sub x/ from flue gases, treatment of dioxins, removal of VOC (volatile organic compounds) and to generate ozone in some ozonizers. A high-energy efficiency operation is necessary for practical applications. Knowledge of the mechanism of streamer discharge propagation is important for the endeavor currently going on worldwide to improve the effectiveness of pulsed discharge systems. In the present work a coaxial cylindrical electrodes system was used. The central electrode was made of stainless steel and had a diameter of 0.5 mm and the outer electrode was made of copper and had an inner diameter of 76 mm and a length of 10 mm. A short length was necessary in order to observe the streamers clearly. A positive pulsed voltage of 67 kV and 200 ns width was applied to the central electrode from a Blumlein generator. Ten photographs were taken with a frame period of 15 ns and exposure of 15 ns. It has been found that the streamer started from the inner electrode and reached the outer electrode in about 80 ns. This leads to an average propagation velocity of the streamers of 4.7 /spl times/ 10/sup 7/ cm/s.