Cathode Spot Velocity of Atmospheric Arc Plasma after Arc Ignition Affected by Self and External Electromagnetic Force between Parallel Electrodes Using 3D Numerical Simulation

Abstract

For visually and quantitatively elucidating the contribution of self and external electromagnetic forces of the cathode spot area to the cathode spot movement, a three‐dimensional electromagnetic thermal fluid simulation program was used to simulate the arc movement between parallel electrodes. According to the analysis results, the cathode spot first step occurred when the electromagnetic force balance of cathode spot area was broken, and the direction of total electromagnetic force at the right side control volume pointed forward. When the current path changes from straight to reentry model, the cathode spot movement became faster because of the self electromagnetic force derived from electrodes. The rapid of cathode spot first step significantly increased along with the arc current increasing, and the increment of self electromagnetic force was more significant than the external electromagnetic force. In conclusion, the application of external magnetic field or the self magnetic field derived from the parallel electrodes benefit to break the electromagnetic force balance of cathode spot area and promote the rapid of cathode spot first step. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.