H₂O 体积分数对纳秒脉冲氮气 DBD 均匀性的影响

In order to produce uniform and reactive plasma and improve the application effect of dielectric barrier discharge (DBD), a nanosecond pulse power supply is used to excite N₂ DBD to achieve large-area homogeneous discharge, and H₂O is added to improve the plasma activity. The effects of H₂O volume fraction on the discharge characteristics of N₂ DBD are studied by electrical and optical diagnosis. The discharge image and voltage and current waveform are quantitatively analyzed by the gray value standard deviation method and equivalent circuit model to obtain the discharge uniformity and electrical parameters, and the change trend of reduced field strength (E/n) is characterized by calculating the ratio of spectral line intensity of N₂ and N2⁺ excited state particles. The results show that, due to the competition mechanism between the ionization reaction of H₂O and the electrons adsorption by H₂O when the volume fraction of H₂O is 0% to 0.6% in N₂/H₂O DBD, the discharge stays in good uniformity. After further adding H₂O, weak filaments appear in the gap, the discharge cannot fill the entire space, and the discharge uniformity decreases. With the increase of H₂O volume fraction, all the transmitted charge, averaged power, energy efficiency, •OH line intensity, and E/n will increase first and then decrease, and reach the maximum value when the H₂O volume fraction is 0.1%. The results are conducive to the preparation of homogeneous, stable and highly active plasma sources at atmospheric pressure.