Numerical Simulation Investigation Of Spatial-temporal Nonlinear Behaviors In The Atmospheric Pressure Dielectric Barrier Discharge

As an important way to generate uniform and stable low-temperature plasma,the atmospheric pressure dielectric barrier discharge(DBD)has attracted much attention in recent years due to its application potential in material processing,film deposition,and surface modification.In essence,DBD is a complex discharge system.There are a large number of rich and complex spatial-temporal nonlinear behaviors after the breakdown moment.At present,some preliminary investigations focus on the characteristics and mechanisms of atmospheric pressure DBD,such as the formation of multi-current pulse discharge,the asymmetric discharge behavior and self-organized patterned discharge mode.However,above researchers are still in the initial exploration stage.In fact,the atmospheric pressure DBD still has abundant nonlinear behavior characteristics,varied physical mechanisms need to be further explored.In order to improve the application value of atmospheric pressure DBD in the industrial field,this paper deeply studies the above-mentioned nonlinear spatio-temporal behavior based on fluid model simulation,and puts forward some important conclusions about the complex spatio-temporal nonlinear behavior of atmospheric DBD:(1)The influence of the air gap width on the multi-current discharge characteristics and the transition process of the discharge mode are clarified.Based on a one-dimensional simulation model,this paper firstly studies the multi-pulse discharge characteristics in atmospheric pressure helium dielectric barrier discharge with the changing gas gap width.The formation mechanism of multi-pulse discharge and discharge mode are analyzed by focusing on the entire width,the total number and the peak value of current pulse and the changing current peak phase.(2)The correspondence between the geometrical symmetry of the dielectric layer and the symmetry of the discharge is confirmed.In order to study the influence of the geometric symmetry of the dielectric layer on the symmetry of the discharge,the thickness of the dielectric layer on one side is changed in the one-dimensional simulation model of the atmospheric pressure argon dielectric barrier discharge.(3)The similarities and differences between the evolution process of the radial filament structure of discharge and other pattern discharge processes are revealed.In the two-dimensional simulation model,the patterned evolution characteristics of the radial discharge column of the atmospheric pressure argon DBD are further analyzed by increasing the amplitude of the applied voltage.The property of background gas explains the nonmonotonic increasing number of discharge channels.(4)The formation and arrangement of the filaments in the discharge space associated with the Penning ionization process and the adsorption reaction process are explained.The background gas in the two-dimensional simulation model adjusts to the mixture of argon and different volume fractions of ammonia gas.The arrangement law of the discharge filaments and the altering discharge intensities of stable discharge filaments are indicated by the Penning ionization process and the attachment reaction process due to the doping gas.