Sapphire single crystals are used widely in a number of modern high-tech applications, such as a substrate material for the epitaxial deposition, optical window material and a filter material for thermal neutron beams. In particular, sapphire single crystals have been highlighted for epitaxial gallium nitride films in high-power laser and light emitting diode (LED) industries. Among the many crystal growth methods, the Kyropoulos process is an excellent commercial method for growing larger, highoptical- quality sapphire crystals with fewer defects. Because the properties and growth behavior of sapphire crystals are influenced largely by the temperature distribution and convection of molten sapphire during the manufacturing process, accurate predictions of the thermal fields and melt flow behavior are essential to design and optimize the Kyropoulos crystal growth process. In this study, computational fluid dynamic simulations were performed to examine the effects of the thermal conditions and geometry on melt convection during Kyropoulos sapphire crystal growth. The evolution of various growth parameters on the temperature, pressure, and velocity profiles were examined using three-dimensional, quantitative, finite volume element-based simulations.

Keywords: Computer simulation, Convection, Radiation, Single crystal growth, Kyropoulos method, Sapphire.