Electro-hydrodynamic processes in an electromagnetic silicon crystallizer
In this publication, the issues of computer simulation of electromagnetic and hydrodynamic processes in an electromagnetic crystallizer mold of a silicon melt of periodic action are considered. The crystallization process proceeds under conditions of additional heating by eddy currents in the melt. The main task of the electromagnetic interaction of currents in the melt and the inductor field is to create a repulsive force to exclude mechanical contact between silicon and the lining surface. When this problem is solved, heat is released in the melt and a vector of forces is formed, which leads to mixing of liquid silicon. These processes affect the transfer of heat between the lower, upper and side surfaces of the cylinder, the shape of which is taken by the melt. To improve the quality of the crystal structure of the ingot, a temperature gradient is formed by controlling heat flows due to the thickness of the lining walls, heating the upper surface and removing heat from the lower base. The appearance of a perturbing action under these conditions can upset the balance of heat flows and lead to the creation of thermal stresses in the ingot, accompanied by microcracks. Simultaneous modeling of all processes occurring in an electromagnetic silicon crystallizer is currently unrealizable on a personal computer. When modeling the process of hydrodynamics in the melt, several geometry options were considered, starting from the maximum volume of the liquid phase and ending with a thin upper layer in the upper part. With a conical shape of the inductor, the distribution of the force vector in the melt depends on the axial coordinate, which leads to a significant decrease in the velocity components as the thickness of the liquid phase decreases. The results of the study showed a rapid decrease in the mixing effect as the thickness of the liquid layer of silicon decreases with a slight change in the overall parameters of the crystallization process.