Numerical simulation of viscoelastic fluid mixing in a T-Y shaped micromixer

علوم کاربردی و محاسباتی در مکانیک

Article 2, Volume 37, Issue 1 - Serial Number 39, April 2025, Pages 17-28   

Document Type: Original Article

DOI: 10.22067/jacsm.2024.87529.1248

Authors

Fatemeh Khalilian; Morteza Bayareh^*

Department of Mechanical Engineering, Shahrekord University, Shahrekord, Iran

Abstract

The current study analyzes the dynamics of the mixing flow of two viscoelastic fluids in a novel T-Y micromixer. An aqueous solution with 10% polyethylene glycol with a molecular weight of 8000 and 0.1% polyethylene oxide with a molecular weight of 2000000, which is a Boger fluid, is selected as a viscoelastic fluid. Using the COMSOL Multiphysics software, the mixing of two viscoelastic fluids will be investigated numerically using the Oldroyd-B constitutive equation. The effect of the inlet velocity, ratio of inlet velocities, and Weissenberg number on mixing efficiency and pressure drop will be presented. The results show that the elastic effect in viscoelastic fluid flow is the main factor in increasing mixing index. At a distance of 2800 μm from the beginning of the main channel, the mixing index reaches from about 46% for the inlet velocity of 0.002 m/s to about 38% for the inlet velocity of 0.006 m/s. With the increase of the Weissenberg number, the mixing index is increased in different cross-sections of the microchannel, because the instability of the viscoelastic fluid is enhanced at higher Weissenberg numbers. Also, it is demonstrated that the mixing index is reduced by decreasing the velocity ratio. Pressure drop is augmented with velocity, Weissenberg number, and velocity ratio.

Keywords

Microfluidics; T-Y micromixer; Viscoelastic fluid; Weissenberg number; Mixing index

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