Research On Mechanism Of Gas-confined Barrier Discharge

In terms of structure,GBD is characterized by an insulating gaseous layer instead of solid dielectric.On the basis of the previous results of GBD researches,we design a tubular glass device with a coaxialjet configuration.It allows helium gas to act as working gas while Ar or Air serves as surrounding gas.The experiments are carried out under the plate or ring electrodes and the research is conducted on the electrical,optical and flow field characteristics of GBD.The experiment setup which uses plate electrodes and the corresponding diagnostic system are built for GBD driven by an AC power supply.We discuss different parameters which affect electrical characteristics and discharge mode including gas flow rate,electrode distance,flow location,dilectric type and external voltage and compare with traditional DBD.It is the first time that GBD operating in the diffuse mode has been demonstrated.When using air or N₂ as insulating gaseous layer,we find the diffuse mode.Moreover,when Ar is used as dielectric material,the phenomenon of stratified glow can be generated.But when the gas layer is replaced by O₂,the diffuse mode disappears.In addition,we use ICCD camera to study the dynamic process of plasma.The images show that the dynamic process is similar to the DBD uniform discharge.Under the ring electrode,the experiments shows that the helium/air GBD can produces diffused plasma jet.In addition,the inner diameter of the electrode,the applied voltage and the distance of the electrode have a great influence on the charge transfer and the initial discharge power.The plasma bullets are observed by the ICCD image with the double ring electrodes.The velocity of the bullets reach the extreme value when pass through the ring electrodes.Meanwhile,the schlieren system also shows that the discharge will make the turbulent region become larger and the turbulent front periodicity develops from the bottom to the top.