A novel 3D numerical model coupling droplet transfer and arc behaviors for underwater FCAW

Based on the VOF method (Volume of Fluid Method), a non-axisymmetric three-dimensional (3D) numerical model was developed in this paper, which coupled the droplet and arc and simulated the typical globular repelled transfer process with large droplet in the underwater wet flux-cored wire arc welding (FCAW) process. The results show that in addition to the action of gravity, surface tension and self-induced electromagnetic force, the droplet is also affected by the gas flow generated by the wire, the gas flow resistance in the bubble and the force caused by metal evaporation. The rotation of the droplet around the wire axis is mainly affected by the gas flow generated by the flux core. But the angle of the droplet deviation from the wire axis is determined by all external forces. The path of current line is changed by the droplet movement, thereby constraining the behavior of the arc. In order to verify the validity of the numerical model, images of the metal transfer are collected by a high-speed camera, and the simulated values are in good agreement with the experimental ones.