利用三电极介质阻挡放电装置,在主放电区产生了较大体积的大气压空气均匀放电.利用光学与电学方法,对主放电特性进行了研究,发现随驱动功率的不同,主放电存在等离子体羽和等离子体柱两种模式,等离子体羽的击穿电压随外加电压峰值的增加而减小.利用光电倍增管对两种放电模式进行了空间分辨测量,发现等离子体羽是以发光光层的形式传播,而等离子体柱是连续放电.通过采集两种放电的发射光谱,对其振动温度和转动温度进行了测量.发现两种放电模式的振转温度均随着UP的增大而降低.
By using a tri-electrode dielectric barrier discharge device, a uniform discharge with fairly large volume is realized in the main discharge region in atmospheric pressure air. The characteristics of the main discharge are investigated by optical and electrical methods. Results show that the main discharge includes two discharge modes with changing the input power of the source, which are a plasma plume discharge and a plasma column discharge. The inception voltage decreases with the increase of the peak value of the applied voltage for plume discharge. It can be deduced that the pre-ionization of air in the main discharge region is important for the main discharge, which results from the UV emitted from the coaxial dielectric barrier discharge. Spatially resolved measurements are conducted on the plasma plume and the plasma column with photomultiplier tubes. It is found that the plasma plume behaves like a plasma bullet that corresponds to a fast moving layer of light emission zone. Comparatively, the discharges at different positions of the plasma column almost volley, which means that the plasma column is of continuous discharge. Through analyzing the optical spectrum emitted from the main discharge, the vibrational temperature and rotational temperature are calculated. Results indicate that both the vibrational temperature and the rotational temperature decrease with the increase of peak value of the applied voltage. These results are of significance for the industrial applications of dielectric barrier discharge.