FLOW-BASED MIXING OF NON-NEWTONIAN FLUIDS IN TLCCM PASSIVE MICROMIXERS: A COMPARATIVE PERFORMANCE STUDY

Abstract

High-efficiency micromixers are crucial in industrial applications. Passive chaotic advection effectively enhances fluid mixing by generating strong secondary flows that help homogenization microscopically. The aim of the present study is to compare different configurations of passive two-layer cross-channel micromixers of various shapes: (TLCCM 1), (TLCCM 2), and (TLCCM 3). The micromixers considered in this study have the same hydraulic diameter and the same equivalent unfolded length of 7.5 mm. Numerical simulations were performed using the Fluent CFD code to solve the momentum equations, the continuity equation, and the species transport equation. The non-Newtonian fluids employed are carboxymethyl cellulose solutions, which are modeled by power-law model with a flow behavior index ranging from 0.49 to 1, and the generalized Reynolds number varies between 1 and 50. Mixing efficiency was evaluated by calculating the mixing degree at different cross- sections. To examine the results obtained through numerical simulations, the mass fraction distributions, pressure losses, and mixing energy costs were presented. The results show that this type of TLCCM micromixer exhibits a high mixing degree, exceeding 0.857 for all values of the generalized Reynolds number and the considered flow behavior index, and it displays relatively low mixing energy costs, particularly for Newtonian fluids.