Three-dimensional numerical simulation on the spreading characteristics of a liquid metal droplet in a horizontal magnetic field

The spreading characteristics of a liquid metal droplet impacting onto a flat solid surface under the influence of a horizontal magnetic field are investigated numerically. The simulated parameters are selected based on our previous experiment but over a wider range of magnetic field (0–5 T). The time evolution of the droplet shape is shown in detail and exhibits an elliptical spreading pattern, namely the droplet is stretched in the direction perpendicular to the magnet lines, which agrees well with the experimental results. To clarify the mechanism underlying the elliptical spreading pattern as well as the asymmetrical rim bulges appeared at the later stage of spreading, the current line distribution and the resultant Lorentz force at two representative times are analyzed quantitatively. The effect of the magnetic field intensity and the initial impact velocity on the anisotropic spreading of droplets is demonstrated by the maximum spreading radius and the time required to reach this maximum extent in two orthogonal directions. Finally, an energy conversion analysis of the overall spreading process is presented and the dissipation of the initial kinetic energy of droplets by Joule heat explains the inhibition effect of the horizontal magnetic field on the average spreading radius.