不同电极结构中SF_6/N_2混合气体正向流注电晕放电特性

Anode-directed streamer corona discharge simulation in different electrode structures in SF_6/ N_2 gas mixtures

宏观上假定气体放电过程中产生的正、负离子束和电子束为流体,采用二维流体动力学模型对SF6/N2混合气体正向流注电晕放电过程进行建模,利用通量校正传输法求解连续方程,通过求解耦合的泊松方程处理空间电荷畸变电场对放电的作用,仿真过程中假设带电粒子的输运参数是折算电场的函数,对比分析了平行板电极间隙、同轴电极间隙和棒-板电极间隙三种电极结构中正向流注电晕放电特性。结果表明:流注电晕的形成加强了流注头部与阳极间的场强,减弱了流注尾部与阴极的场强。只有流注头部所在位置的初始场强足够大时放电才能继续发展,否则放电转化为稳定的流注电晕放电。

Gas discharge can be analyzed on macroscopic methods that the mobility of electrons,positive ion and negative ions is a flow. A two-dimensional fluid dynamics model is used to analyze streamer corona discharge mechanism in SF6/ N2 gas mixtures. The flux corrected transport technique is used to solve fluid equations for charged particles. The effect of electric field distortion by space charge as time goes is settled by coupling Poisson electric equation to the fluid equations. During the simulation,it is assumed that the transport coefficients of gas mixtures are only the function of reduced electric field. The discharge characteristics of parallel plate electrode gap,the coaxial electrode gap and rod-plate electrode gap are compared and analyzed. The simulation results show that streamer corona strengthens the electric field between the anode and the streamer corona and weakens the electric field between the cathode and the streamer. The discharge will continue when the electric field strength in front of streamer is big enough,or discharge will become stable.