初始电子浓度对空气中针板间隙正极性流注放电的影响

Influence of Initial Electron Concentration on Positive Streamer Discharge in Pin-plate Air Gap

为揭示环境中初始电子浓度对气体放电过程的影响,利用等离子体流体力学模型研究了大气压下5mm针-板空气间隙的流注放电过程。采用的等离子体流体力学模型包括了电子、正负离子连续性方程和电场的泊松方程。研究发现:5mm针板空气间隙下流注放电的通道半径约为0.1～0.3mm;随着间隙中初始电子浓度的增加,流注头部电场强度逐渐减小,流注发展的平均速率逐渐增大,流注贯穿间隙的时间逐渐减小;初始电子浓度对板电极表面电场强度、流注通道内电场强度和流注通道半径的影响可以忽略。

In order to reveal the influence of initial electron concentration on gas discharge in pin-plate air gap,positive streamer discharges in a 5 mm pin-plate air gap with different initial electron concentrations are investigated using a hydrodynamic drift-diffusion model.The model consists of a set of continuity equations of positive ions,negative ions,and electrons,which are coupled with the Poisson＇s equation.The results show that the radii of streamer channels are about 0.1-0.3 mm during streamer discharge;with an increase of initial electron concentration in the gap,the maximum electric field of streamer head decreases,while the average velocity of streamer propagation increases and the time that the streamer costs to bridge the whole gap decreases.However,initial electron concentration shows ignorable influence on the radius and the electric fields of plate electrode surface and the electric field inside streamer channel.