Three‐dimensional turbulent flow in agitated vessels with a nonisotropic viscosity turbulence model

Abstract

Solutions of the time‐averaged equations of motion with a nonisotropic k‐e model were developed for the three‐dimensional turbulent flow field in turbine stirred tanks. These results were validated with the measurements of three velocity components with a hot wire anemometer and literature data. The nonisotropic turbulence model considered the rotation and curvature effect of the turbulence with a turbulent Richardson number term and accounted for the important three‐dimensional effects through the nonisotropy of the viscosity. Also, it was found that a frequently used isotropic k‐ϵ turbulence model did not describe this three‐dimensional turbulent flow field.

Modeling of the Performance of Industrial Bioreactors with a Dynamic Microenvironmental Approach: A Critical Review

“…Applying the experimental investigation of Ståhl Wernersson [5] to estimate the kinetic energy at the centerline of the turbine (Eq. (5)), one can note that the numerical results of Ju et al [63] are in good agreement with experimental data (Tab. 1).…”

“…Using the ke turbulence model, Lee et al [62] concluded their numerical investigation with the remark that improvements to the physical model were required in order to correctly predict the values of k near the impeller. With respect to anisotropy, Ju et al [63] employed a nonlinear k-e model and reported much better agreement with experimental results, both in the impeller and bulk regions for mean velocity components and fluctuation profiles. These authors also presented diagrams of simulated turbulent kinetic energy and contours of energy dissipation rates in a vertical plane of the stirred reactor.…”

“…Other, more appropriate, turbulence models should be used, either based on time-averaging (e.g., modified k-e models [59,63,65] or preferentially Reynolds stress models [62,64] which are generally part of the commercially available CFD codes CFX-F3D, Fluent, and Phñnics) or models based on space-averaging, i.e., Large Eddy Simulation (LES) [66]. Brief descriptions of LES, including its advantages, can be found in Piomelli et al [67] and Olsson [68].…”

Comparison of Experimental and Computational Particle Trajectories in a Stirred Vessel

“…Ju et al [11] used a nonisotropic viscosity turbulence model. Kresta and Wood [2] and Ranade and Joshi [3] simulated the flow with the black box method and the k-e turbulence model.…”

Mixing and Chemical Reactions

“…In some of these simulations, the flow in and out, L S and ε, were based on experimental data (Patterson, 1975;Mann and Knysh, 1984). It is now possible using standard CFD codes to numerically compute spatial distributions of Reynolds-averaged variables of the turbulent flow and mixing of miscible fluids with similar viscosities and densities in almost any geometry (see Hutchings et al, 1989;Bakker and van den Akker, 1990;Ju et al, 1990;Bakker and Fasano, 1993;Perng and Murthy, 1993;Dilber and Rosenblat, 1995;Harvey et al, 1995;Fox, 1995;Armenante and Chou, 1996;Zipp and Patterson, 1998). Circulation patterns and distribution of turbulence intensities are generally good and predict the trends correctly, but the values of the turbulent quantities k and ε are not always correct.…”