The two-scale turbulence concept is recommended for modeling the turbulence in a baffled vessel equipped with a Rushton-type turbine impeller. A three-equation isotropic turbulence model is proposed that employs the balance equations for: the kinetic energy of the large scale vortices; the kinetic energy of the inertial subrange eddies; and the dissipation rate of the small-scale turbulence. The energy transfer rate from the large-scale vortices is prescribed algebraically. Flow patterns are modeled by solving the transport equations for vorticity, stream function, and tangential momentum. The Reynolds stresses are modeled by means of the effective viscosity, based on the three-equation model of turbulence. The calculated profiles of the mean velocity at the tank wall agree with experimental data obtained in the same system by means of a Pitot tube.established a model to describe turbulent flow in the impeller region for a Rushton-type turbine impeller. The method commonly used to predict velocity fields in turbulent flows is based upon the concept of turbulent viscosity, which is evaluated from the local values of overall kinetic energy of turbulence k and its dissipation rate t. Balance equations of turbulent quantities must be solved simultaneously with the balance equations for mass and the mean momentum. Applied ad hoc to the mixing vessel, the k-6 model fails to give acceptable results of the turbulence parameters in mixing vessels, as indicated in the results of Platzer (1981). The approach applied here extends the classic k-c model to include the turbulence energy scales k, and kT, where the former represents the production-scale vortices and the latter represents the inertial range eddies. The extended model is employed here to construct an algorithm for the computation of profiles of mean velocity, kinetic energy of turbulence, and dissipation rate of turbulence.The model is compared with experimental data to evaluate the reliability of the numerical predictions. The numerical results for the mean velocity profiles in the wall region are compared with experimentally measured velocities for a laboratorysize vessel. The wall region presents many distinct advantages in measurements for validation of this model. These include verification of the secondary circulation, sufficiently high mean velocities for satisfactory accuracy, moderate levels of turbulence, and a check in the region where the assumption of axial symmetry may be violated. Wall measurements are preferable to impeller measurements because of large degrees of anisotropy

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