Research On The Microphysical Process Of Positive Glow Corona Discharges In N₂/O₂ And Influencing Factors

Positive glow corona is one of the most common forms of discharges involved in nature and industry.Although the existing experimental and simulation studies have provided a preliminary understanding of the physical process of glow corona discharge,there are still several fundamental research questions that scholars are concerned about but have not been able to explain.In this paper,a detailed numerical simulation study is carried out focusing on the microphysical process of positive glow corona and the main influence factors.The research work has important scientific value for deepening the understanding of positive glow corona discharges.Firstly,a one-dimensional plasma chemical reaction model of positive glow corona under the coaxial structure is established by combining the measured ion mobilities in the literatures.A comprehensive kinetic scheme（CKS）for N₂/O₂ mixture is considered in the model.The Helmholtz equations are used to solve the photoionization process.The simulation results are compared with the classical fluid model considering an averaged kinetic scheme（AKS）.The reasons leading to the difference in the predicted results of the two models are analysed and the importance of detachment between O^-and N₂ on the triggering of glow corona in air is found.An experiment is carried out,verifing the validity of the simulation model.Secondly,based on the CKS model,the microphysical mechanism of the recovery of electric field near the anode before the first glow corona oscillation is investigated.The spatial and temporal distribution of the main positive and negative ions during the stable glow corona are given.The dominated chemical reactions between ions are analysed.These studies deepen the understanding of the microphysical processes of positive glow corona.Next,a one-dimensional plasma chemical reaction model of the glow corona discharge in N₂/O₂/H₂O mixture is developed.The effect of humidity on the glow corona current and surface electric field is investigated.The distribution of main positive and negative ions in the ionization layer and drift region during the glow corona discharge in humid air is analysed.The effect mechanism of H₂O on the dominant chemical reaction processes between ions during the glow corona discharge is revealed.Then,the positive glow corona discharge in high-pure nitrogen is simulated based on the CKS model.The effects of several major electron sources,such as the detachment and photo-ionization,on the waveforms of glow corona current are discussed.The triggering mechanism of glow corona oscillations in high concentration nitrogen is revealed.The unreasonableness of the hypothesis on bremsstrahlung radiation proposed by Akishev is pointed out.The positive glow corona discharges in“pure nitrogen”industrial products is simulated,and the critical oxygen concentration for the phenomenon of glow corona oscillations in nitrogen-oxygen mixtures is investigated.Finally,the CKS model is used to preliminarily analyze the effects of the applied voltage,wire radius,air pressure,nitrogen-oxygen ratio and humidity on the distribution of O,O₃,OH and H₂O₂ produced during positive glow corona discharge.The obtained conclusions provide a certain reference for the industrial application of positive glow corona.