Numerical Simulation Of Uniform Atmospheric Pressure Discharge Controlled By Dielectric Barrier Between Unsymmetrical Electrodes

A review is presented of the article associated with the development of plasma that is considered as "the fourth state" of the substance and its application, from the conception of plasma. It provides the arc discharge, the corona discharge, the dielectric barrier discharge, and the plasma jet, as well as their applications in industry in this paper. Uniform atmospheric-pressure discharge (APD) controlled by dielectric barriers has attracted considerable attention since its inception because of its advantageous properties for industrial applications. In recently years, experimental and modeling studies on uniform APD have been carried out and some preliminary insights into uniform APD have been obtained.The space and time distributions of the electric field and the electron, the metastable helium atoms and the ion densities, as well as the time evolution of the voltage and the discharge current density in dielectric-barrier-controlled discharge which between unsymmetrical electrodes at atmospheric pressure are calculated by solving the one-dimensional continuity and momentum equations for electrons and ions, coupled to the current continuity equation. The properties of dielectric-barrier-controlled discharge between unsymmetrical electrodes at atmospheric pressure under the conditions of the second electron emission coefficient and different driving frequency are discussed and analyzed. The evolution disciplinarian of electron temperature is also analyzed. In calculation, the discretization of continuity equation is performed in accordance with semi-implicit and the electric field is solved by the current conservation instead of the Poisson's equation. The simulation results show that the peak values of the discharge current and the electric field are asymmetry in the former and latter half cycle, because of the different secondary electron emission coefficiency of the metal electrode and the dielectric electrode. We find, at certain conditions, in dielectric-barrier-controlled discharge, which between unsymmetrical electrodes at atmospheric pressure, can operate in two different modes, i.e. Townsend and glow modes. This two discharge modes have completely different electrical characteristics and spatial structures. The transition between them can be controlled by the external parameters. When the current reaches the positive and negative maximums, the distributions of the electric field, electrons and ions density have the same properties as the typical Townsend discharge. The properties of discharge current are determined by the external conditions. The metastable helium atoms play an important role in the discharge. They mainly produced in the active phase of the discharge and keep its relatively high concentration at the cathode. In the case of smaller gap width, multiple current pulses can be formed in each half-cycle of the applied voltage duo to the increases of surface density of the accumulation charges leading to the enhancement of the induced electric field. In the case of certain constant gap width, the applied voltage and frequency can influence the number and the amplitude of current pulses. The evolution disciplinarian of electron temperature is also analyzed in this paper, and it keeps its relatively high concentration at the cathode. The electrons have higher energies at the electrodes.