Effect of Reynolds Number on Laminar Mixing in an Annular Tube Combining Two Crossed Secondary Flows

Abstract

To improve static and continuous mixers, several methods have been proposed in the literature. Herein, two well-known passive intensification configurations were applied to an annular laminar flow and numerically studied. Residence time distributions (RTDs) and Poincaré sections were examined to investigate the dispersion of the particles. These two approaches show that geometric perturbations of the walls improve the mixing level for all Reynolds numbers investigated. Above Re = 300, the increase in mixing can be attributed to chaotic advection within the flow. Finally, a general reactor model that allows the RTD in the annular tube to be predicted with high confidence is proposed.