Semi-Batch Liquid-Liquid Taylor Vortex Flow: Comparison of 3-D and 2-D Eulerian-Eulerian CFD Simulations and Experimental Measurements for Fluid Flow Patterns and Droplet Holdup

In this paper, semi-batch liquid-liquid Taylor-Couette flow regimes have been studied in a vertically-oriented reactor using both experiments and Eulerian-Eulerian multiphase computational fluid dynamic (CFD) models. This flow features competition between wall-driven azimuthal flow and buoyancy-driven axial flow of the droplet phase. The present study utilizes a water as the continuous phase and n-hexane as the droplet phase, while two key operating parameters (inner cylinder rotation speed and feed rate of hexane) are varied in order to modulate the azimuthal and axial Reynolds numbers. Fluid flow regimes are delineated as a function of these parameters. Other quantities considered here include dispersed phase droplet size and size distribution, droplet holdup, droplet spatial distribution. Both three-dimensional and axisymmetric two-dimensional CFD simulations are compared with experimental measurements, and the limitations of two-dimensional simulations are discussed.