Prediction of flow pattern in stirred tanks: New constitutive equation foreddy viscosity

The CFD simulations were carried out for the flow produced by two axial flo w impellers, namely a pitched-blade downflow turbine (PBTD, N-p = 2.1) and a hydrofoil impeller (N-p = 0.34) by the impeller boundary condition approa ch. The tank was fully baffled, and the flow regime was turbulent. An attem pt has been made to develop a new constitutive equation for C-mu in the des cription of eddy viscosity given by a standard K-E model. The resulting pre dictions with the new eddy viscosity relation are compared with the experim ental data. Also the comparison is sought with the predictions of impeller boundary condition approach using k-epsilon model with the standard and mod ified turbulence parameters (Ranade et al. Chem. Eng. Commun. 1989, 81, 225 ), zonal model of Sahu et al. (Ind. Eng. Chem. Res. 1998, 37, 2116) and the sliding mesh simulation using a standard k-epsilon model. For all these ca ses, energy balance has been established and compared with the experimental data. This paper also presents a critical review of the computational flui d dynamic (CFD) studies pertaining to the prediction of the flow produced b y the axial flow impellers.