Numerical Simulation of Direct Current Glow Discharge in Air with Experimental Validation

Abstract

An improved self-consistent, multicomponent, and two-dimensional plasma model for simulating low-pressure air glow discharge is presented. In the model, both the plasma hydrodynamics model and chemical model are considered, which include 12 species and 27 reactions. The discharge voltage–current characteristics and spatial profiles of electron temperature predicted by the model are in good agreement with experimental measurements. On the basis of the validated model, the characteristics of plasma evolution are investigated in detail. The simulation results show that the electron impact ionization reaction of N2 shows the highest rate for electron production. N2+ and O2+ are the dominant positive ions, and N2+ is smaller in amount on density than O2+ at about one order of magnitude. The production rate of N2+ is greater than that of O2+ in the entire discharge process. This indicates that the positive ions and electrons play a prominent role in determining the characteristics of plasma. With time progresses, the conductive current density increases at the cathode, but decreases at the anode. Moreover, the conductive current density at the cathode is much smaller than that at the anode. It is shown that the presented developed plasma model can provide valuable insights into the physical mechanisms of low-pressure air glow discharge, and suggests ways to optimize practical engineering.