Numerical Simulation Of A 2D Crystal Growth Problem: Latent Heat Effects And Solid-liquid Interface Morphology (original) (raw)

Modeling of convection phenomena in Bridgman-Stockbarger crystal growth

1985

Thermal convection phenomena in a vertically oriented Bridgman-Stockbarger apparatus were modeled by computer simulations for different gravity conditions, ranging from earth conditions to extremely low gravity, approximate space conditions. The modeling results were obtained by the application of a state-of-the art, transient, multi-dimensional, completely densimetrically coupled, discrete-element computational model which was specifically developed for the simulation of flow, temperature, and species concentration conditions in two-phase (solid-liquid) systems. The computational model was applied to the simulation of the flow and the thermal conditions associated with the convection phenomena in a modified Germanium-Silicon charge enclosed in a stationary fused-silica ampoule. The results clearly indicated that the gravitational field strength influences the characteristics of the coherent vortical flow patterns, interface shape and position, maximum melt velocity, and interfacial...

Modelling and Controlling of Weak Laminar Flows When Grow Crystals from the Melt by the Ahp Method

Introduction. Widely recognized methods for single crystal growth are known to be characterized by a complex, instable in behavior melt flow, appearing at the interaction of buoyancy, thermocapillary and forced convections. Previously, some methods of growth have been proposed (1, 2) when an additional heater is arranged inside the crucible, in the melt, at the phase interface. Serving as a partition (1), the submerged heater splits the melt in two zones. Buoyancy con- vection is relatively weak in the zone of crystallization (under the heater); a weak melt flow driven by the motion of the crucible with the crystal about the heater is laminar and stationary. The zone about this submerged heater supplies the zone of crystallization with the melt. The processes, occurring in the two zones, almost do not affect each other. When thermocouples are arranged along all boundary surfaces and an axial heat flux is implemented at the interface (2), during the entire growth cycle there appears ...