脉冲参数对大气压He中一维射流阵列放电特性的影响

Influence of Pulse Parameters on Discharge Characteristics of One-Dimensional Plasma Jet Array in He at Atmospheric Pressure

射流阵列是扩大等离子体射流处理面积的有效手段,而如何提高射流阵列的稳定性和均匀性对于其实际应用至关重要。为了获得均匀、稳定的射流阵列,利用纳秒脉冲激励在大气压He中产生了稳定的一维等离子体射流阵列放电,利用发光图像和电气特性测量诊断了其光学特性和电学特性,研究了电压幅值、上升时间和重复频率对射流阵列放电均匀性的影响,进而获得射流阵列均匀放电的激励源条件,并结合放电机理对试验结果进行了分析。结果表明:合理地调控脉冲电源参数可在环环电极结构中产生均匀的一维等离子体射流阵列,改变电压幅值不影响射流阵列的均匀性,但可增加射流阵列的放电能量、传输电荷和射流等离子体羽长度,提高射流阵列的放电强度;脉冲上升时间对射流阵列传输功率、放电能量和等离子体羽长度影响较小;脉冲重复频率对放电能量和传输电荷的影响较小,但其是影响射流阵列均匀性的主要因素。射流阵列中不均匀的电场分布和各单元中残留活性粒子的差异是影响均匀性的主要原因,降低频率可减小残留活性粒子对放电的影响,进而提高射流阵列的均匀性。

Grouping up many individual plasma jets to construct jet arrays is an effective way to enlarge the downstream treatment area of a single plasma jet,while the stability and uniformity of jet array are essential for its industrial application.In this paper,in order to obtain a stable and uniform jet array,a 1D atmospheric pressure plasma jet array in He is generated driven by a nanosecond pulse source,and its discharge characteristics are investigated with optical and electrical diagnoses including images and voltage-current waveforms.The influence of pulse parameters such as voltage amplitude,rising time and pulse frequency on discharge characteristics is studied,and the optimal pulse parameters for generating a uniform jet array are obtained,with the results being analyzed.Results show that a uniform 1D He plasma jet array can be generated under proper pulse parameters with the ring-ring electrode structure.Increasing the voltage amplitude has little effect on discharge uniformity,but can increase the discharge energy,transported charge and plume length,thus improve the discharge strength of jet array.The rising time has slight effect on discharge energy,transported charge and uniformity,and the pulse frequency significantly influences the uniformity,while has little effect on discharge energy and transported charge.The non-uniformity of jet array is due to the non-uniform distribution of electrical field and different content of residual active particles in each channel.Decreasing pulse frequency can reduce the influences of residual active particles on the discharge and is thus beneficial for obtaining a uniform jet array.