Diagnosis of Atmospheric Pressure Helium Cryogenic Plasma Jet
SONG Peng1,3, LI Zheng-kai2, CHEN Lei2*, WANG Xiao-fang1, LONG Wu-qiang1, ZENG Wen2
1. School of Energy and Power, Dalian University of Technology, Dalian 116024, China
2. Aerospace Engineering Institute, Shenyang Aerospace University, Shenyang 110136, China
3. School of Mechanical and Electrical Engineering, Dalian University for Nationalities, Dalian 116605, China
Abstract：In order to accelerate the process of helium plasma jet’s engineering，a stable helium plasma jet was produced in the atmosphere through a self-designed coaxial Dielectric Barrier Discharge structure with a discharge frequency of 10 kHz. By analyzing the voltage and current waveform under different working conditions, it can be found that simply increasing the volume flow of helium gas can only increase the current pulse slightly, but has little effect on the discharge time and the number of current pulses. However, when the peak discharge voltage is increased, the current pulse amplitude increases significantly. The types of active particles, electron excitation temperature and electron density of atmospheric pressure helium plasma jet were diagnosed by emission spectroscopy. The results show that the main active particles of helium plasma jet are He I atom, N2 second positive band system, N+2 first negative band system, hydroxyl (OH), H atom Balmer line system (Hα, Hβ) and O atom. It shows that although the purity of the helium gas used in this test has reached 99.99%, there is still a small amount of air remaining. At the same time, the air in the atmosphere will be sucked into the discharge space and be ionized. It can be found that the relative spectral intensity of the main active particles showed an upward trend with the increase of the volume flow of helium gas and the increase of the peak discharge voltage. The electronic excitation temperature under different test conditions was calculated by the Boltzmann slope method between 3 500 to 6 300 K. With the increase of the discharge peak voltage and helium gas’s volume flow rate, the electron excitation temperature basically shows a rising trend. However, due to the presence of a reverse electric field, the electronic excitation temperature may show a downward trend at some certain peak voltages; According to the Stark broadening principle, the electron density of the atmospheric pressure helium plasma jet was calculated, and it is found that the electron density can reach the order of 1015 cm-3 while increasing the peak voltage and helium volume flow can effectively increase the electron density in the plasma jet. The study of these parameters is of great significance for the application of helium plasma jets.
Key words：Atmospheric pressure; Heliumdielectric barrier discharge; Emission spectroscopy; Electron excitation temperature; Electron density
[1] LIU Ding-xin, HE Tong-tong, ZHANG Hao(刘定新, 何桐桐, 张 浩). High Voltage Engineering(高电压技术), 2019, 45(7): 2329.
[2] Xie Q, Lin H F, Zhang S, et al. Plasma Science and Technol., 2018, 20(2): 025504.
[3] WANG Xin-chao, DAN Min, ZHANG Fan, et al(王新超, 但 敏, 张 帆, 等). Chinese Journal of Vacuum Science and Technology(真空科学与技术学报), 2020, 40(3): 233.
[4] YAO Shui-liang, ZHANG Xu-ming, LU Hao(姚水良, 章旭明, 陆 豪). High Voltage Engineering(高电压技术), 2020, 46(1): 342.
[5] HE Li-ming, LIU Xing-jian, ZHAO Bing-bing, et al(何立明, 刘兴建, 赵兵兵，等). Journal of Aerospace Power(航空动力学报), 2016, 31(7): 1537.
[6] HE Li-ming, CHEN Gao-cheng, ZHAO Bing-bing, et al(何立明，陈高成，赵兵兵，等). High Voltage Engineering(高电压技术), 2018, 44(3): 856.
[7] SHEN Yuan, WANG Rui-xue, ZHANG Cheng, et al(沈 苑, 王瑞雪, 章 程, 等). High Power Laser and Particle Beams(强激光与粒子束)，2016, 28(5): 055001.
[8] TIAN Si-li, WANG Rui-xue, ZHANG Cheng, et al（田思理, 王瑞雪, 章 程, 等）. Proceedings of the CSEE(中国电机工程学报), 2018, 38(1): 330.
[9] SUN Zhen-yu, SUN Min, CAO Hui-juan, et al(孙振宇, 孙 敏, 曹慧娟, 等). High Voltage Engineering(高电压技术), 2019, 45(10): 3383.
[10] ZHAO Yong, WANG Rui-xue, ZHANG-Cheng, et al(赵 勇, 王瑞雪, 章 程, 等). Transactions of China Electrotechnical Society(电工技术学报), 2019, 34(16): 3472.
[11] ZHANG Yi-fan, GAO Jun, LEI Peng, et al(张秩凡, 高 俊, 雷 鹏, 等). Acta Physica Sincia(物理学报), 2018, 67(14): 145202.
[12] ZHANG Wei, CHEN Lei, SONG Peng, et al(张 维, 陈 雷, 宋 鹏, 等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2018, 38(12): 3678.
