ABSTRACT
ABSTRACT: In the paper, numerical computation is employed to study characteristics of heat transfer in a Kyropoulos furnace at the beginning of the cooling process. Comparative analyses are made to investigate effects of different heater locations on heat transfer and stress evolution in the sapphire crystal. The results show that the high von Mises stress is located in the region near the sapphire seed crystal, the crystal bottom center, and the crystal surfaces with the concave curvature. As the bottom heater gets closer to the support rod, temperature in the crystal increases obviously, in addition, the maximum von Mises stress transforms from the bottom center of the crystal to the ‘bottleneck’ with a downtrend. A small distance between the bottom heater and the supporter rod is helpful to reduce the stress avoiding cracks in the crystal ingot.
