Simulation of Metal Droplet Sputtering and Molten Pool on Copper Contact under Electric Arc

Kai BO  Xue ZHOU  Guofu ZHAI  Mo CHEN  

IEICE TRANSACTIONS on Electronics   Vol.E101-C   No.9   pp.691-698
Publication Date: 2018/09/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E101.C.691
Type of Manuscript: Special Section PAPER (Special Section on Recent Development of Electro-Mechanical Devices)
arc erosion,  molten metal jet,  molten pool,  hydrodynamics of molten metal,  

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The micro-mechanism of molten pool and metal droplet sputtering are significant to the material erosion caused by breaking or making arcs especially for high-power switching devices. In this paper, based on Navier-Stokes equations for incompressible viscous fluid and potential equation for electric field, a 2D axially symmetric simplified hydrodynamic model was built to describe the formation of the molten metal droplet sputtering and molten pool under arc spot near electrode region. The melting process was considered by the relationship between melting metal volumetric percentage and temperature, a free surface of liquid metal deformation was solved by coupling moving mesh and the automatic re-meshing. The simulated metal droplet sputtering and molten pool behaviors are presented by the temperature and velocity distribution sequences. The influence mechanism of pressure distribution and heat flux on the formation of molten pool and metal droplet sputtering has been analyzed according to the temperature distribution and sputtering angles. Based on the simulation results, we can distinguish two different models of the molten metal droplet sputtering process: edge ejection and center ejection. Moreover, a new explanation is proposed based on calculated results with arc spot pressure distribution in the form of both unimodal and bimodal. It shows that the arc spot pressure distribution plays an important role in the metal droplet ejected from molten pool, the angle of the molten jet drop can be decreased along with the increment of the arc spot pressure.