Simulation studies of the hydrodynamics in high-temperature solutions for crystal growth. V. Shape of the crystal/liquid interface in the presence of simultaneous free and forced convections

The formation conditions of a concave, convex or flat crystal/liquid interface in the presence of simultaneous free and forced convections have been investigated using model liquids. Simultaneous free and forced convections with both the same and opposite flow directions have been considered. The interface shape was found to depend on the direction and rate of the resultant convection flow under the crystal. The formation conditions of a flat interface for liquids having kinematic viscosities of 0.001·10^?3 – 0.5·10^?3 m²/s and for crystal diameters of 10, 15 and 20 mm, respectively, have been established. These conditions have been compared with the optimum conditions found experimentally by other authors for the growth of several kinds of crystals from high-temperature solutions by the TSSG method and from melts by the Czochralski method. The comparison has shown that the model proposed describes well the real processes.