Andreeva O. The use of ordered convection structures in viscous fluid layers with solid boundaries for the homogenization of the oxide phase of structural steels

The use of a convective cell with solid boundaries, which arises in the metal melt in the vacuum-arc remelting of steel, has an upward flow in the center, and a downward near the wall of the crystallizer, is proposed for the homogenization of the oxide phase of the structural steels. The regularities of occurrence of convective flow in horizontal layers of a viscous, incompressible liquid with solid and mixed boundary conditions, which are heated from below, are determined. It is shown that in this layer the number of disjointed cylindrical convective cells increases with the temperature of the bottom of the container from one - two cells to a large number of them, which form cells of Benard. An analytical solution of the Relay problem with solid boundary conditions is obtained, neutral curves are constructed, the physical model of the dependence of the number of Nusselt on the Rayleigh number is formulated, the influence of the surface tension on the parameters of the convective cell is taken into account. The diameter of the convection cells (in units of depth of the layer) is determined: the experiment is 2,5 – 2,6, the theory – 2,46. The use of the "hollow fish-bone" cathode was proposed to increase homogenization of zirconium dioxide powder in the ingot. It was shown that for a cathode of the type "hollow fish-bone", homogenization of particles of zirconium dioxide is possible at their very small size (less than 90 ± 5 nm).