Simulation studies of the hydrodynamics in high-temperature solutions for crystal growth. IV. Flow rates in the presence of free and forced convections proceeding in the same direction

An experimental simulation study has been carried out on the convection flow rate under the crystal during its growth from a high-temperature solution by the TSSG method with prevailing heating of the crucible bottom and in the presence of simultaneous free and forced convections occurring in the same direction. It has been established that with increasing proportion of forced convection the rate of the resultant upflow passes through a minimum. Immediately before this minimum the flow is instable with respect to time. The minimum is observed at a definite ratio between the determining dimensionless numbers Gr and Re, which depends on the crystal diameter alone. A correlation allowing determination of the flow rate after the minimum has been found.