Effect of crucible geometry on melt convection and interface shape during Kyropoulos growth of sapphire single crystal

In this work, the numerical simulations were performed to investigate the rolls of crucible shape on temperature distribution, melt convection behavior and shape of the melt/crystal interface during the Kyropoulos sapphire crystal growth process. Cylindrical crucibles with different bottom corner radii were considered, and the Kyropoulos growth process was simulated using the finite volume method. Through numerical analyses, it was found that an increase in bottom corner radius of the crucible decreased the convexity of melt/crystal interface and the velocity of convectional flows of the molten sapphire during crystallization. As a consequence, it was concluded that the crucible with a curved bottom had advantages for the crystallization of the sapphire using the Kyropoulos method.