交流和纳秒脉冲激励氦气中等离子体射流阵列放电特性比较

Comparison on Discharge Characteristics of the Helium Plasma Jet Array Excited by Alternating Current and Nanosecond Pulse Voltage

为获得大气压下均匀稳定的大尺度低温等离子体射流,用交流(AC)和纳秒(ns)脉冲电源激励在氦气中产生一维射流阵列放电,比较两种电源激励射流阵列的放电均匀性、瞬时功率、平均功率和发射光谱强度等放电特性和参量,并通过拍摄气流通道的纹影图像和估算射流单元之间的库仑力作用,研究和分析射流阵列的射流单元之间的流场和电场相互作用。结果表明,采用ns脉冲电源可以有效地提高射流阵的均匀性,增加等离子体羽长度、瞬时功率和粒子谱线强度,降低平均功率。不同于AC激励射流阵列,ns脉冲激励的射流阵列中两侧的射流单元几乎不发生偏转。采用ns脉冲激励可以同时减少气体加热作用和库仑力的排斥作用,从而有效地抑制射流单元之间的流场和电学相互作用,是提高射流阵列均匀性的主要原因。

To obtain the stable atmospheric pressure low-temperature plasma jet with large scale and good uniformity,a one-dimensional plasma jet array discharge in He was generated excited by alternating-current(AC)and nanosecond(ns)pulse voltage.Discharge characteristics and parameters of the jet arrays were compared,including the uniformity,instantaneous power,averaged power and intensities of optical emission spectrum.The hydrodynamic and electrical interactions among jets were analyzed by capturing the Schlieren images of gas channels and estimating the effect of Coulomb force among jets.The results show that the jet array excited by ns-pulse voltage can improve the downstream uniformity,increase plasma plume length,instantaneous power and intensity of optical emission spectrum,and reduce averaged power consumption.Different from the case in AC excitation,the jet array excited by ns pulse voltage has nearly no divergence in the lateral plumes.The ns pulse power source can also reduce the effects of gas heating and Coulomb repulsion force,thereby suppressing the hydrodynamic and electrical interaction among jets,which is the main reason for improving the uniformity of downstream plume.