Parametric study of the Crossing elongation effect on the mixing performances using short Two-Layer Crossing Channels Micromixer (TLCCM) geometry

In this study we investigate the mixing performances of a modified micromixer which achieves a very good mixing quality that can be compared to other micromixers proposed recently, our idea proposes a modification of the crossing zone to reduce the unit number. The numerical simulations have been carried out at low Reynolds numbers using the CFD Fluent code to solve the 3D momentum equations, continuity equation, and the species transport equations. The elongation of the crossing zone is defined by a parameter called aspect ratio (l/W). A parametric study was realized using five values of aspect ratio (l/W) from 0 to 1 in a wide range of Reynolds numbers: from 0.2 to 80. To analyze the obtained results through the numerical simulations, the mass fraction contours, velocity vectors, velocity profiles, and pressure losses were presented in different cross-sectional planes and positions. The selected geometry (with l/W = 1) has excellent mixing performances where the obtained mixing index exceeds 85.67% for Re = 0.2 and reaches 99.22% for Re = 50, it also has a lower pressure drop compared to other geometries studied recently. Therefore, the selected micromixer shows high mixing performances at low Reynolds numbers, so it can be employed to improve fluid mixing in various microfluidic systems. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.