Modeling Highly Unsteady Current-driven Liquid Metal Free-Surface MHD Flows

The flow of electrically conducting liquids in response to a highly unsteady applied current (or magnetic field) is of practical interest in nuclear fusion, and metallurgy. Analytical and semi-numerical methods have been used to model such flows for a number of years, but suffer from serious model limitations when there are large and rapid deformations of the free surface, and in complex geometries. We present a candidate time-accurate simulation method which uses a magnetic vector potential and a scalar electric potential in a general purpose high performance computing software. Variants of this method are often seen in eddy current analysis, but applications in free surface MHD appear limited and rather restrictive. The model permits the flow of current into the conducting elements, and can resolve highly unsteady phenomena and the skin effect. We will present the method with verification, and apply it to the mini-SLiC experiment at General Fusion, where a pool of liquid lithium in a steel vessel is rapidly propelled by an electric current pulse (about 1ms) and exhibits interesting dynamics. We will compare numerical results with observed experimental data.