Simulation of particle flow in molten pool of electric contact of power switch

The electric arcing between the electrodes of a power switch makes the electrode surface partly molten and results in a molten pool, which is the essential reason of sputter erosion of contact materials. Understanding the characteristics of particle movement or flow in the molten pool is very important for the prediction of sputter erosion volume. The authors analyze the forces working on the contact molten pool to make the pool flow. These forces are: surface tension caused by the disequilibrium temperature distribution in the molten pool; buoyancy force; electromagnetic force. A model of fluid flow in the molten pool, based on hydrokinetic theory, is presented; it considers the coupling effect between heat transfer and fluid flow. With ANSYS software, the distribution of the fluid field and the flow velocity of the molten pool are calculated. The paper also discusses the influence of arc energy, surface tension and the material properties on the flowing characteristic in the molten pool. Under the same arc energy, the change of electromagnetic force is the main reason for fluid velocity change.