摘要
In this paper,self-designed multi-hollow needle electrodes are used as a high-voltage electrode in a packed bed dielectric barrier discharge reactor to facilitate fast gas flow through the active discharge area and achieve large-volume stable discharge.The dynamic characteristics of the plasma,the generated active species,and the energy transfer mechanisms in both positive discharge(PD)and negative discharge(ND)are investigated by using fast-exposure intensified charge coupled device(ICCD)images and time-resolved optical emission spectra.The experimental results show that the discharge intensity,number of discharge channels,and discharge volume are obviously enhanced when the multi-needle electrode is replaced by a multihollow needle electrode.During a single voltage pulse period,PD mainly develops in a streamer mode,which results in a stronger discharge current,luminous intensity,and E/N compared with the diffuse mode observed in ND.In PD,as the gap between dielectric beads changes from 0 to250μm,the discharge between the dielectric bead gap changes from a partial discharge to a standing filamentary micro-discharge,which allows the plasma to leave the local area and is conducive to the propagation of surface streamers.In ND,the discharge only appears as a diffusionlike mode between the gap of dielectric beads,regardless of whether there is a discharge gap.Moreover,the generation of excited states N_(2)^(+)(B^(2)∑_(u)^(+))and N2(C^(3)Π_(u))is mainly observed in PD,which is attributed to the higher E/N in PD than that in ND.However,the generation of the OH(A^(2)∑^(+))radical in ND is higher than in PD.It is not directly dominated by E/N,but mainly by the resonant energy transfer process between metastable N_(2)(A^(3)∑_(u)^(+))and OH(X^(2)Π).Furthermore,both PD and ND demonstrate obvious energy relaxation processes of electron-to-vibration and vibration-to-vibration,and no vibration-to-rotation energy relaxation process is observed.
作者
秦亮
李瑶
郭浩
姜楠
宋颖
贾锐
周雄峰
袁皓
杨德正
Liang QIN;Yao LI;Hao GUO;Nan JIANG;Ying SONG;Rui JIA;Xiongfeng ZHOU;Hao YUAN;Dezheng YANG(Key Laboratory of Materials Modification by Laser,Ion,and Electron Beams(Dalian University of Technology),Ministry of Education,Dalian 116024,People’s Republic of China;School of Electrical Engineering,Dalian University of Technology,Dalian 116024,People’s Republic of China;State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System,Luoyang 471003,People’s Republic of China;School of Physics and Materials Engineering,Dalian Minzu University,Dalian 116600,People’s Republic of China)
基金
supported by National Natural Science Foundations of China(Nos.51977023 and 52077026)
the Fundamental Research Funds for the Central Universities(No.DUT23YG227)。
