Numerical Study Of Atmospheric Pressure Surface Dielectric Barrier Discharge Actuator

In recent years,the atmospheric pressure dielectric barrier discharge plasma actuator has received extensive attention due to its advantage in airflow control.Its configuration is simple compared to traditional airflow control actuator,and it does not change the shape of aero foil so it has negligible effects on aero foil’s dynamics.And dielectric barrier discharge plasma actuator has less energy consume than the conventional actuator.With the existence of the dielectric barrier plate,the discharge current is in low level,thus the energy consume is in low level.Although both experimental and numerical researches have been carried out on atmospheric pressure dielectric barrier discharge plasma actuator,further investigation is still needed to study some unclear discharge behaviors as well as the potential physical mechanism.In this dissertation,based on a two-dimensional fluid model,the research on atmospheric pressure dielectric barrier discharge is carried out with a purpose to study the discharge behaviors and physical mechanism.We simulated air as the working gas in a two-dimensional dielectric barrier discharge model and use COMSOL Multiphysics software to simulate atmospheric pressure dielectric barrier discharge plasma actuator by setting parameters,meshing and computing.In Chapter 3,the analysis of the actuator discharge behaviors is performed under different operation conditions.By analyzing the temporal-spatial distribution of electron density,space charge density,electron temperature and electrical potential,the study of the dielectric barrier discharge actuator discharge behaviors and potential physical mechanism is performed.The discharge cycle of the atmospheric pressure dielectric barrier discharge actuator consists of two kind of phases.Current pulses occurs during the discharge cycle as found in discharge voltage-current waveform figure.In the positive-going phase,the current pulse is in high level and the frequency is low;in the negative-going phase,the current pulse is in low level and the frequency is high.When the positive-going voltage is applied to the naked electrode,the streamer occurs periodically.The periodically formed streamer expands along the dielectric surface from the exposed electrode to the opposite direction.Periodic breakdown of the air is also observed in the negative-going phase;however the streamer is not formed and the current pulse frequency is much higher than in positive-going phase.The simulation results under different operation parameters such as the amplitude of the applied voltage,the thickness and the relative permittivity of the dielectric plate is analyzed.In the positive-going phase and the negative-going phase,the amplitude and the frequency of the current pulses increase as the amplitude of the applied voltage increases.In the positive-going phase and the negative-going phase,the amplitude and the frequency of the current pulses increase as the thickness or the relative permittivity of the dielectric plate increases.The voltage amplitude,the thickness and the relative permittivity of the dielectric plate has the similar effect on the discharge behavior,in that these parameters can affect the potential difference between the naked electrode and the dielectric plate surface,and the electric intensity in the discharge area.