In this paper, the numerical computation was performed to investigate the influence of the heat shields of sapphire crystalfurnace on temperature distributions for the Kyropoulos sapphire crystal growth process. The heat shields with different shieldradius, shield layers and the shield materials were considered, the Kyropoulos growth process was simulated by the finiteelementmethod. It is found that radial temperature gradient of crystal would increase along with the increase of the shieldradius and the decrease of the layers of top shield. If properly increasing the shield radius and the layers of the top shield, axialtemperature gradient in crystal would decrease, but the layers of side shield have little influence on the temperature in crystal. The heat shields made of different materials were compared by analyzing the crystal temperature distribution. Simulationresults showed that temperature distribution in crystal by W-Mo shield is much closer to that of ZrO2 shield, both oftemperature distribution are higher than that of graphite heat shield.

Keywords: Kyropoulos technique, Sapphire, Numerical simulation, Heat shield, Thermal field analysis