The influence of thermocapillary or Marangoni convection on the growth of silicon crystals is investigated in an industrial Czochralski crucible using a quasi direct numerical simulations approach. An optimized parallel-vector block-structured finite volume Navier-Stokes equations solver is extended to include the effects of thermocapillary convection. Owing to the presence of surface tension gradients, the magnitude of the radial velocity towards the crystal becomes high at the free surface. Consequently, the temperature along the free surface is increased. The thermocapillary convection reduces the temperature fluctuations below the crystal and the free surface of the melt. However, below the crystal, the turbulent kinetic energy, k, is higher at different melt depths when the thermocapillary effect is taken into account. It is necessary to study the above-mentioned effects of surface tension driven convection since they influence the quality of the crystal. (C) 2003 Elsevier Science Ltd. All rights reserved.