Numerical Analysis And Experimental Study On The Air Discharge In Short Gap

During the process of gas discharge,luminescence is the most obvious and basic physical phenomenon.When the gas molecule is excited,it will jump back from the high energy level to the low energy level and release energy which is called photon.As a result of particle transition,the discharge channel glows.Compared with other measurement methods of discharge stream,the method of collecting optical signal is a non-contact measurement.Therefore,it do not affected by electric field and magnetic field and had many advantages,such as good selectivity,high sensitivity,easy operation,and high accuracy,and had no disturbances on the discharge,and so on.This paper adopts the method of collecting light signals to study air glow discharge phenomenon under short gap.The paper focuses on the mechanism of gas discharge under atmospheric pressure,using the stream discharge fluid dynamics model,numerically analyzing the rod-plate electrode structure and proposing that the stream discharge consists of two phases.The first stage lasts about 4 ns and during this time the radius of the plasma channel increases and stream channels become conical at last.The second stage is a phase of stationary propagation and the radius of the stream channel is almost the same.We can obtain the electronic temperature distribution characteristics,spatial electric potential distribution characteristics,negative ion concentration distribution characteristics,positive ion concentration distribution characteristics,electronic concentration distribution characteristics,spatial distribution characteristics of the electric field and change characteristics of microscopic physical quantities,which are consistent with the experimental results obtained by relevant scholars.In order to obtain the phenomenon of air discharge,under normal atmospheric pressure,respectively do the discharge experiments with rod-plate electrode and rod-rod electrode in different air gap,and collect instant optical signal of air discharge with rod-plate electrode and rod-rod electrode in short air gap.With the increase of applied voltage,the stream discharge markedly improved,which is easily observed.With the increase of applied voltage,the discharge area of head of the rod electrode enlarges.And in accordance with the experimental results,electron temperature,electron density are calculated and they are consistent with the numerical analysis results.We can compare the observe results with the numerical analysis results in order to verify the correctness of the numerical analysis results.