tailieunhanh - Air Pollution Part 12

Tham khảo tài liệu 'air pollution part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 268 Air Pollution voltage the discharge mode changed from a streamer to a glow-like discharge with a large discharge current same as the positive one. It should be mentioned that discharge emission recorded near the surface of the rod electrode after the negative stramer head left the central rod is due to the surrounding photoionization and then the heat of the rod electrode surface. The propagation velocity of the streamer heads at certain time vstreamer can be given by streamer AL At 5 where AL and At are the developed distance and time progress for its propagation from the streak images respectively. The velocity of positive streamer is the same at certain applied voltage for different charging voltages and the velocity increases with increasing applied voltage to the rod electrode. This may be due to the applied voltage to the rod electrode having a strong influence on the motion of the streamer head since there is a higher conductivity plasma channel between the rod and streamer head. The velocity of a negative streamer is approximately half that of positive streamers and also increases by increasing the absolute value of the applied voltage to the rod electrode. The propagation velocity of the streamer heads was mm ns for a positive peak applied voltage of 15 60 kV of and mm ns for a negative peak applied voltage -28 -93 kV respectively. The electric field for streamer onset was constant at 15 kV for all different applied voltages in positive streamers. Likewise the applied voltage at streamer onset was -25 kV for negative streamers. The electric field on the surface of the rod electrode before discharge initiation Eo were 12 and 20 MV m respectively. Eo is given by applied h. --------- 0 6 rln ri where Vappiied r T1J and r2 are the absolute value of the applied voltage to the rod electrode the distance from the center of the rod electrode the radius of the rod electrode and the inner radius of the cylinder electrode respectively 35 38

TỪ KHÓA LIÊN QUAN