This paper presents a three-equation turbulence model for the determination of turbulent quantities, such as the mean square temperature variance, turbulence kinetic energy and its dissipation rate. The conservation equations are discretized by the finite volume method SOLA [Hirt et al., Los Alamos Laboratory, Report LA-5852 (1975)]. The model is tested for a grid-generated flow and for a fairly hot axisymmetrical turbulent air jet. The results of the present calculations are compared with the experimental data of other authors. The comparison shows that the good agreement, for the thermal field, depends fundamentally on the value of the turbulent Prandtl number and the ratio of time scales of turbulent temperature and velocity field.