Generation of swirling liquid metal flow in a cylindrical channel under the action of stationary magnetic fields

Abstract

This paper investigates numerically a transit flow of liquid metal in a cylindrical channel, in which the metal is exposed to a constant magnetic field of complex configuration that causes swirling of the flow. From a theoretical standpoint, the relevance of the study stems from the fact that swirling flows of electrically conducting matter from the depth of cosmic bodies (stars, planets) generate cosmic magnetic fields and interact with them. Of practical interest is the possibility of non-contact excitation of intense mixing flows by constant magnetic fields that do not produce time-varying electromagnetic interference. Using these flows it is possible to homogenize the properties and temperature of the liquid metal coolant in a cylindrical pipeline, or to intensify its heat exchange processes. The magnetic field is generated by a pair of Helmholtz coils oriented orthogonally to the channel axis and a system of electrodes of special configuration that induce a magnetic field along the channel axis. The interaction of the through flow with the magnetic field created by the Helmholtz coils generates an electric current, which is mainly orthogonal to the channel axis. The interaction of this current with the magnetic field produced by the system of electrodes gives rise to the electromagnetic force, whose azimuthal component causes the flow to swirl. The numerical study was carried out using the original mathematical model that describes magnetohydrodynamic processes within the induction-free approximation. It has been shown that constant magnetic fields can maintain permanent swirling of the flow. The dependencies of the swirl intensity on the process parameters have been obtained, and the diagrams of the resulting flow regimes have been constructed. The results of the contact and non-contact generation of magnetic fields by the second source are compared.