Numerical simulation of external magnetic field effect on arc plasma after molten metal bridge breaking under different electrode opening velocities

In this study, a three-dimensional electromagnetic thermal fluid simulation program was developed to simulate arc movement numerically while considering metal vapor generated from a molten metal bridge along with an electrode opening under external magnetic field application. The change in the physical properties of the arc and the increment rate of the arc voltage per unit length under different electrode opening velocities were analyzed by applying an external magnetic field with different intensities. It was found that the current path of the arc became dispersed when the electrode opening velocity was high because the metal vapor generated from the molten metal bridge remained dominant and highly concentrated. Before the completion of the electrode opening process, the difference in the increment rate of the arc voltage per unit length at different electrode opening velocities became more significant when an external magnetic field was applied. This was because under high and low electrode opening velocities, the cross-sectional area of the arc became narrow and broad, respectively.