Analysis on Dynamic Characteristics of Corona Discharge in Low Concentration Methane-Air Mixture at Micro-Nano Scale

The detection of low concentration CH4 gas in underground coal mines is very important, and the micro-nano ionization sensor can quickly and accurately detect the composition and concentration of the gas. However, there is a lack of theoretical analysis of such sensors at the microscopic level. Based on the theory of fluid dynamics, a two-dimensional needle-plate discharge model is employed to simulate and study the dynamic discharge process of low concentration methane-air mixture at micro-nano scale. Based on the model, various characteristics during discharge period are analyzed, including the spatiotemporal evolution of electron density, the variation of electric field intensity and output current density. By changing the concentration of CH4 at atmospheric pressure, it can be concluded that the output current density of the ionization sensor decreases with the increase of CH4 concentration. Also, this research has a certain guiding significance for the preparation of micro-nano ionization methane sensor.