STRUCTURE OF SOLIDIFIED ALUMINUM MELT IN CRUCIBLES OF CIRCULAR AND SQUARE CROSS-SECTIONS IN REVERSE REGIMES OF ROTATING MAGNETIC FIELD

摘要

In the paper, experimentally and numerically is studied the combined effect of reversibly rotating magnetic field and travelling magnetic field on the aluminum alloy at its directional solidification in crucibles of circular and square crow-sections. In experiments, a liquid alloy (93%Al7%Si) was stirred in a reverse regime by a rotating magnetic field under the action of a continuously applied travelling magnetic field. It has been found that as soon as the rotating magnetic field intensity increases the size of grains in the ingot reduces. Analysis of the results has revealed a relationship with a pronounced extremum between the grain size and the period of reversals of the rotating magnetic field. To determine the hydrodynamic parameters affecting the structure of the ingot in the reverse mode of MHD stirring, a numerical study was performed. Significant effects of the rotating magnetic field reversals on the hydrodynamic and thermal characteristics of the flow have been found.