考虑电压上升影响的“针-板”空气间隙直流负流注放电特性研究

DC Negative Streamer Discharge Characteristics of'Needle-plate'Air Gap Considering Influence of Voltage Rise

负流注放电过程是一个高度非线性动力学过程,且发展过程复杂。该文针对“针–板”电极结构、1cm空气间隙,建立短空气间隙负流注放电模型并通过仿真试验验证模型合理性,分析外加上升时间及电压幅值对负流注放电发展过程空间电场强度、带电粒子浓度、流注发展速度、放电电流变化特性的影响。随负流注由“针”电极向“板”电极发展,放电区域内的轴线电场强度、电子浓度在短暂升高后呈现先降低后升高的变化趋势;随外加电压上升时间增大,流注头部的电场强度和电子浓度呈非线性上升趋势,外加电压上升时间T=0.01ns上升到T=2ns时,流注发展平均速度降低3.38mm/ns;随外加电压幅值增大,负流注头部的电场强度及电子浓度呈非线性上升趋势,外加电压幅值U_(0)=-20kV上升到U_(0)=-25kV时,流注发展平均速度上升2.7mm/ns。

The negative streamer discharge process is a highly nonlinear dynamic process with complex development.In this paper,a short air gap negative streamer discharge model is established for the'needle-plate'electrode structure and the 1cm air gap,and the rationality of the model is verified by simulation experiments.The effects of the applied voltage rise time and amplitude on the spatial electric field intensity,the charged particle concentration,the streamer development speed and the discharge current variation characteristics of the negative streamer discharge development process are analyzed.As the negative streamer develops from the'needle'electrode to the'plate'electrode,the axial electric field intensity and the electron concentration in the discharge region increase briefly and then decrease first and later increase.As the rise time of the applied voltage increases,the electric field intensity and the electron concentration of the streamer head increase nonlinearly.When the rise time of the applied voltage T=0.01ns increases to T=2ns,the average streamer velocity decreases by 3.38mm/ns.With the increase of the applied voltage amplitude,the electric field intensity and the electron concentration of the negative streamer head show a nonlinear upward trend.When the applied voltage amplitude increases from U_(0)=–20kV to U_(0)=–25kV,the average streamer velocity increases by 2.7mm/ns.