Numerical Simulation of Gliding Arc Plasma Motion Characteristics

Abstract

In this paper, a mathematical model of DC gliding arc plasma was established based on magneto-hydrodynamic theory (MHD), and the finite element software COMSOL was used to solve the coupling process of electromagnetic field, temperature field and velocity field. The effects of flow rate, electrode throat and voltage on the gliding arc velocity, temperature and current density distribution were studied. The results show that the gliding arc discharge presents a cyclic process of arc breakdown, elongation, disappearance, and re-breakdown. The flow rate has a significant effect on the arc characteristic distribution, and the gas blowing makes the arc discharge appear “arc shape”. When arc breakdown, the arc temperature and current density have the maximum value at the electrode. As the arc gradually stabilizes to form an arc column, the maximum moves to the center of the arc column and gradually decreases along the radial direction. As the flow rate increases, the maximum velocity increases, while the temperature and current density decreases. With the electrode throat gap narrowing, the temperature and current density reach the maximum quickly. It only needs 0.4 ms to reach the maximum when gap is 2 mm. And the smaller the gap, the easier it is for the arc to re-breakdown. The temperature and current density increase with the voltage. This work reveals the motion characteristics of the gliding arc between the electrodes. The influence of characteristic parameters on gliding arc plasma is clarified. It provides a certain basis for optimizing the structure of the gliding arc reactor.