Simulation of flow hydrodynamics in a pulsed solvent extraction column under turbulent regimes

Mathematical description and numerical simulation of the flow hydrodynamics is carried out for the case of a pulsed turbulent flow in extraction columns with internals of alternating discs and rings (DRC). In this work, the flow hydrodynamics (flow structure, velocity fields, flow energy parameters etc.) are studied related to the geometrical parameters of the internals and to pulsation intensity. It is found that the flow pattern of a DRC is characterized by the presence of permanent large vortices as well as by permanent zones of low and high levels of the turbulent kinetic energy. The latter is responsible for the drop break-up processes and for interphase surface formation. A simple dependence of the turbulent energy parameters (turbulent kinetic energy k and its dissipation rate epsilon) on the pulsation intensity is estimated. The influence of the internals design on the stage energy level is characterized by constants independent on the pulsation intensity. The results are also used to create a data bank of local values of velocity, pressure, turbulent kinetic energy and its dissipation rate under various stage geometry parameters and various intensities of the pulsation applied to the flow. The contents of this data bank are useful for development of correlations for prediction of important process parameters used in apparatus design and scale-up. (C) 1998 Published by Elsevier Science S.A. All rights reserved.