Design And Optimization Of High Efficiency Corona Discharge Device Based On Fluid-chemical Model

With the development of the economy,the environmental problems facing China are becoming more and more serious,especially the shortage of water resources and smoggy weather.Charged particle catalyzed artificial rainfall and haze removal techniques are important tools to solve these problems,and the generation of high concentration plasma in a wide range of space is the key to the successful application of these technologies.Corona discharge is an important method for generating high concentration plasma in a wide range of space.It is simple in equipment and low in cost,and is most suitable for applications such as charged particle catalyzed artificial rainfall and haze removal.In these applications,the plasma concentration determines the water vapor condensation efficiency and the haze particle removal efficiency.How to increase the corona discharge plasma concentration is a key factor determining its application effect.Therefore,improving the structure of the corona discharge device and increasing its discharge power density and plasma generation concentration are of great significance for the application of corona discharge plasma generating devices in charged particle catalytic artificial rainfall and haze removal.In this paper,a corona discharge simulation model based on fluid-chemical model is established,and the discharge efficiency of different electrode structures is analyzed and compared.The optimization design of the corona discharge device is completed based on the analysis results,and relevant experimental research is carried out.Firstly,a fluid-chemical model describing the evolution process of particles in corona discharge space is established,and Boltzmann equation is solved based on two-term approximation method.The electron energy distribution function?EEDF?is obtained,and a series of electron transport parameters required for solving the model are obtained.By analyzing the relationship between the electron energy distribution function and the average energy of the electron,the relationship between the average energy of the electron and the reduced electric field,the discharge mechanism of the corona discharge is further explored.Secondly,based on the established fluid-chemical model,the numerical simulation of the corona discharge of wire-plate,rod-plate and sheet-plate structure under normal temperature and pressure is carried out.By comparing the electron temperature,potential distribution,electron density and positive and negative ion distribution?N₂⁺,O₂^-?of the three structures,and the charged particle generation efficiency of the three electrode structures,the electrode structure was selected.The simulation results show that the wire-plate electrode discharge is a stable and weak discharge intensity of the Townsend discharge,while the rod-plate electrode and the sheet-plate electrode are intense discharges of the streamer discharge,which means that the discharge intensity of rod-plate and sheet-plate is higher than that of wire-plate discharge,and more charged particles can be produced.By comparing the discharge parameters of the sheet-plate electrode and the rod-plate electrode in detail,the conclusion that the discharge strength of the sheet-plate electrode is higher than that of the rod-plate is obtained.Finally,this paper carried out a sheet-plate electrode related experimental study,studied the discharge volt-ampere characteristics of the sheet-plate electrode and its discharge development process.At the same time,a new DC corona discharge device based on chip-plate electrode is designed,and the air suspension particle removal experiment is carried out by this device.The discharge characteristics,voltage level and voltage polarity of the new corona discharge device are studied.As a result of the influence of the airflow speed on the removal efficiency of the device,it was found that the voltage level had a significant effect on the cleaning effect of the device,followed by the voltage polarity,and the influence of the airflow velocity was relatively weak.