Liquid metal pump now ready for experimentation

A special pump has been built to sustain liquid metal flows in a broad range of velocities. A set of permanent magnets is mounted on a ferromagnetic rotor. This is attached via a steel shaft to an AC induction motor, as the prime mover. As the rotor rotates, a rotating field is generated, which is partly "frozen" in the liquid metal surrounding the rotor. Therefore, as the field rotates, the liquid metal rotates as well, along with a slip factor. Note that the liquid metal never enters in contact with moving metal parts; rather, it is dragged by the magnetic field. This is to avoid electrical contact, for future stabilization experiments. Non-magnetic materials were used for bolting of the stator to reduce the induction heating at the intersections. The liquid metal circuit is partly ducted and partly free-surface. 3D printers have been used to implement the main channel of the pump, its connector and holder and the "Tile" (in red in the video) where the free-surface liquid metal flow can be studied and stabilized.
A pot containing liquid metal (Galinstan) is placed few cm above the main channel of the pump. In this case, we are not using the device as a pump, but as a source of time- and space-dependent magnetic field. Induction results in electromagnetic forces that generate a flow and make the liquid metal surface uneven. Similar undesired effects are expected in liquid walls in a fusion reactor, where the field will also be non-uniform and non-constant. This is the motivation for our work on liquid metal stabilization.
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