Control of Crystallization of Non-Ferrous Metals by Changing the Phases of the Supply Currents of a Linear Induction Stirrer
G. L. Losev, A. D. Mamykin
Institute of Continuous Media Mechanics, Ural Branch, Russian Academy of Sciences, Perm, Russia
Keywords: magnetohydrodynamics, hydrodynamics, traveling magnetic field, crystallization, linear induction machine
Abstract
The crystallization of a gallium alloy in a rectangular flat cuvette located vertically under external electromagnetic influence has been studied experimentally. It has been shown that the speed of movement and shape of the crystallization front can be effectively controlled by changing the power parameters of the electromagnetic stirrer. A mode characterized by intense mixing flow and significant inhomogeneity of the crystallization front has been selected by varying the amplitude of electromagnetic forces. In this mode, changing the phase angles of the supply currents of the linear induction machine allows one to fundamentally change the topology of hydrodynamic melt flows at a constant power supply of the stirrer. This, in turn, leads to a change in heat and mass transfer characteristics and hence the conditions in the interfacial region, making it possible to indirectly control the homogeneity of the crystallization front and, to a lesser extent, the phase transition rate. The contribution of convection to flow formation and its influence on the crystallization process have been studied. In particular, it has been shown that thermal convection can lead to the formation of additional vortex structures near heat exchangers, which prevents metal crystallization.
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