Static electromagnetic shaping of liquid metal drops in transient magnetic fields

M. Conrath - Ch. Karcher

Department of Mechanical Engineering, Technische Universitaet Ilmenau, Postfach 100565, 98684 Ilmenau, Germany

Abstract
The present study deals with the shaping of liquid metal drops using time-dependent magnetic fields. We consider perfectly non-wetting drops placed on a horizontal electrically insulating plate. The magnetic field is generated by an inductor that carries an electrical current I with a time dependence according to I ∝ √{t₀+t}. In this case, the interaction between the magnetic field and the induced eddy currents within the liquid metal results in static Lorentz forces. These Lorentz forces can be used to squeeze the drop counteracting both gravity and surface tension. We derive a nonlinear ordinary differential equation for the drop contour. This equation is integrated numerically using a standard shooting method. We apply our method to various values of drop volume and magnitude of the Lorentz forces. The results prove that such magnetic fields allow for strong static squeezing of liquid metal drops. Figs 6, Refs 17.