In the present work, numerical modeling has been performed to analyze heat transfer and melt convection during bismuth germanate Bi4Ge3O12 (BGO) crystal growth by the Czochralski growth method. In addition to global heat-transfer modeling, the suggested model accounts for the radiative heat exchange in the crystal and melt convection together with the crystallization front formation. The model helped to analyze the modification of the growth setup made by including additional heater. The numerica(l) predictions obtained with CGSim software agree well with available experimental data. (c) 2009 Elsevier B.V. All rights reserved.