Mixing Performance of a 3D Micro T-Mixer with Swirl-Inducing Inlets and Rectangular Constriction.

Jinxin Zhang,Xiaoping Luo

doi:10.3390/mi9050199

Abstract

In this paper, three novel 3D micro T-mixers, namely, a micro T-mixer with swirl-inducing inlets (TMSI), a micro T-mixer with a rectangular constriction (TMRC), and a micro T-mixer with swirl-inducing inlets and a rectangular constriction (TMSC), were proposed on the basis of the original 3D micro T-mixer (OTM). The flow and mixing performance of these micromixers was numerically analyzed using COMSOL Multiphysics package at a range of Reynolds numbers from 10 to 70. Results show that the three proposed 3D micro T-mixers have achieved better mixing performance than OTM. Due to the coupling effect of two swirl-inducing inlets and a rectangular constriction, the maximum mixing index and pressure drop appeared in TMSC among the four micromixers especially; the mixing index of TMSC reaches 91.8% at Re = 70, indicating that TMSC can achieve effective mixing in a short channel length, but has a slightly higher pressure drop than TMSI and TMRC.

Highlights

In recent years, microfluidic systems have received great attention for their extensive applications involving sample preparation and analysis, flow chemistry, drug delivery, and chemical and biological analysis [1,2,3,4,5]
The low Reynolds number makes the flow in the micromixers laminar, and the mixing processes are dominated by molecular diffusion
This work proposed three novel 3D micro T-mixers with swirl-inducing inlet and rectangular constriction to enhance the mixing of two fluids

Summary

Introduction

Microfluidic systems have received great attention for their extensive applications involving sample preparation and analysis, flow chemistry, drug delivery, and chemical and biological analysis [1,2,3,4,5]. Cortes-Quiroz et al [34] conducted further research on the effect of the aspect ratio of the mixing channel on the flow characteristics and mixing performance in the 3D T-mixer. The results indicated that the swirl flow was produced by the fluid coming from two inlet channels of the 3D T-junction, which could enhance mixing even at low Reynolds numbers. Compared to the typical T-mixer, this design can obtain a mixing improvement of more than twice due to that the obstacles in the inlet channels narrow and displace the fluid streams so they come into the T-junction at different vertical levels, intertwine and form a vortex flow in the mixing channel. IIssoommeettrriiccaannddtotoppvvieiwews sofotfhtehe3D3DT-Tsh-sahpaepdedmimcriocmroimxeixrse:r(sa:)(Oa)TOMT,M(b,)(TbM) TSMI, (ScI), T(cM) TRMC,R(Cd), (TdM) TSMC.SC

Governing Equations and Boundary Conditions

Mesh Independency

Validation

Flow Characteristics

Conclusions