Research On Modeling And Simulation Of KHz AC Coaxial CH₄/He/O₂ Atmosphere DBD

Plasma assisted methane combustion can make improvements in the stability of flame combustion and the efficiency of combustion,and reduce the emission of pollutants,with the activated particles such as excited particles and free radicals which generated by methane discharge.It can provide theoretical guidance for methane assisted combustion to study the evolution of electron density,electron temperature,electric field in discharge space and particle density with parameters in different time and space.The 1-D CH4/He/O2 simulation model is established by using Comsol to set up model parameters such as relevant control equation,reaction equation and boundary condition.Firstly,the temporal and spatial distribution of discharge parameters such as electron density,electron temperature and electric field intensity,in CH4/He/O2 discharge process under 20kHz power supply and 20kV Voltage Peak to peak sinusoidal AC excitation source are studied,and the reaction path and axial distribution of particle density are analyzed.Then,the changes of electron temperature,electric field intensity and particle density along with power frequency and voltage peak peak to peak are studied at the peak time of current pulse B,and the changes of transfer charge in discharge space are analyzed by Lissajous figure.Finally,the effects of dielectric material,discharge gap and dielectric thickness on the discharge characteristics of CH4/He/O2 gas mixture are studied.The changes of CH3,CHs+and other particle density with time in different space positions in the discharge gap are analyzed,which provides theoretical basis for the structural optimization and electrode design of DBD reactor.The simulation results show that CH4/He/O2 discharge has a discharge channel similar to glow discharge,and the density of H and CH3 is the highest among several typical particles which reach the order of 1020m-3,and The axial distribution of the density of CH3 and CH4+ is similar to that of the electron temperature distribution with the increase of the peak to peak voltage,the discharge process is enhanced,and the transfer charge in the discharge space is increased,but the transfer charge is basically unchanged with the increase of the power frequency;the O and H densities increase with the discharge time in the positive cycle,The distribution of density of CH5+ with time in different space is basically similar to that of loop current.CH3 has fast conversion and short life in discharge space.In this paper,the study of CH4/He/O2 discharge characteristics and plasma parameters can provide theoretical basis for methane assisted combustion and conversion as well as reference for DBD electrode design and optimization.Figure[49]table[2]reference[78]...