Three-Dimensional Asymmetric Model and Simulation of Double Cathode Spots Crater With Different Kinds of Protrusions in Vacuum Arc

A 3-D asymmetric model has been proposed to study the formation and development of copper cathode spots on different shapes of protrusions and the interaction with a nearby spot in a vacuum arc. In addition to comparing protrusions of different shapes, the effect of the distance between two spot craters is also considered. The article compared the morphology and temperature of the erosion process of the spots with spherical protrusions, two different ellipsoidal protrusions, and the case of no protrusions as a comparison. Through the simulation calculation, it is found that there will be an obvious liquid metal ridge at the intersection of the two spots no matter what kind of shapes of protrusions when the two cathode spot craters are not very close. The maximum surface temperature of the cathode always appears at the junction of the two spots. For the protrusion with a certain volume and distance, the temperature rise of the cathode is higher when its height is higher. When the shape of the protrusion remains unchanged, the closer distance between the two spots causes the temperature to rise more. The temperature rise caused by the distance factor is more obvious than the shape factor.