Abstract
In this work, a special crucible shape with a round shape for the outer wall and an inverted conical shape for the inner wall is presented to investigate the thermal and flow transport, as well as the shape of the crystal–melt interface during the Kyropoulos sapphire crystal growth, by using the numerical simulation method. The results show that the growth system with proposed crucible shape can result in more suitable thermal and flow fields, a lower convexity at shouldering and equal-diameter growth stage and a higher convexity at the following stage. Thus, the results are benefit for the quality of the sapphire crystal.
•We propose a special crucible with inverted conical inner wall.•The inverted conical crucible decreases the temperature and velocity in the melt.•The inverted conical crucible can get the lowest convexity at initial growth stage.•The convexity becomes higher at the last growth stage.•Inverted conical crucible is proved helpful to obtain high-quality sapphire.