In the present work, an advanced numerical model is suggested to analyze heat transfer and flow pattern in sapphire crystal growth by the Kyropoulos technique. The new approach accounts for radiative heat exchange in the crystal and convection in the melt, and provides prediction of the crystallization front shape. The model allowed the analysis of several growth setup designs and selection of an optimal configuration. The numerical predictions performed with the CGSim software (www.semitech.us) agree well with available experimental data obtained in optimized crystal growth process reported for the first time. (C) 2007 Published by Elsevier B.V.