This paper presents a comparison between numerically calculated and measured temperature distributions in turbulent flow in a laboratory model for a CZ large silicon single crystal industrial growth system with a horizontal DC magnetic field. The laboratory model consists of an electrically heated 20" crucible with low-temperature InGaSn melt, a water-cooled metallic crystal model, and a magnet system creating a horizontal magnetic field in the range 0-0.16T. Distributions of time-averaged temperature values in various cross sections in the melt are obtained from measurements by a multichannel thermocouple system. A 3D numerical model for the scalar potential induced in the melt by the velocity field in the horizontal DC magnetic field is implemented in the HD program package CFD-ACE+(TM)(V2003). For 3D HD calculations, moderate grids and the RNG k-epsilon turbulence model are used. Comparisons between calculated and measured temperature distributions in various cross sections are carried out for the cases with and without crucible and crystal rotation and with and without the magnetic field. The agreement is generally good. but some local discrepancies appear in the cases with the crystal rotation. (C) 2003 Elsevier B.V. All rights reserved.