Numerical Study of T-Shaped Micromixers with Vortex-Inducing Obstacles in the Inlet Channels

Abstract

To enhance fluid mixing, a new approach for inlet flow modification by adding vortex-inducing obstacles (VIOs) in the inlet channels of a T-shaped micromixer is proposed and investigated in this work. We use a commercial computational fluid dynamics code to calculate the pressure and the velocity vectors and, to reduce the numerical diffusion in high-Peclet-number flows, we employ the particle-tracking simulation with an approximation diffusion model to calculate the concentration distribution in the micromixers. The effects of geometric parameters, including the distance between the obstacles and the angle of attack of the obstacles, on the mixing performance of micromixers are studied. From the results, we can observe the following trends: (i) the stretched contact surface between different fluids caused by antisymmetric VIOs happens for the cases with the Reynolds number (Re) greater than or equal to 27 and the enhancement of mixing increases with the increase of Reynolds number gradually, and (ii) the onset of the engulfment flow happens at Re≈125 in the T-shaped mixer with symmetric VIOs or at Re≈140 in the standard planar T-shaped mixer and results in a sudden increase of the degree of mixing. The results indicate that the early initiation of transversal convection by either symmetric or antisymmetric VIOs can enhance fluid mixing at a relatively lower Re.

Fundamental Studies of Rapidly Fabricated On-Chip Passive Micromixer for Modular Microfluidics

“…The results of the present study are very promising when compared to other related studies using complex on-chip structures for mixing procedures [ 15 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. In some of these studies, external microelectrodes were used and integrated on the chip to generate frequency switching transverse EOF for chaotic mixing [ 15 , 24 ].…”

“…In some of these studies, external microelectrodes were used and integrated on the chip to generate frequency switching transverse EOF for chaotic mixing [ 15 , 24 ]. Other studies developed complex on-chip structures of T-, Zigzag, and Serpentine types [ 25 , 26 ]. Finally, some only presented the model design of the micromixer and showed the simulation results [ 27 , 28 , 29 ].…”

Numerical Investigation of Mixing by Induced Electrokinetic Flow in T-Micromixer with Conductive Curved Arc Plate

“…Their results showed that by decreasing the frequency and increasing the amplitude of the magnetic field, the mixing efficiency increases, and a better distribution of particles within the channel can be achieved. Wu and Lai [34] conducted a numerical study on a T-shaped micromixer with a vortex generator obstacle at the input. They studied the effect of geometric variables such as obstacle distance and obstacle angle on micromixer performance.…”

Editorial for the Special Issue on Analysis, Design and Fabrication of Micromixers

“…The current special issue includes 12 research papers [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. The topics of the papers are focused on design of micromixers [ 2 , 3 , 4 , 5 , 6 , 7 , 9 , 12 , 13 ], fabrication [ 8 , 9 , 12 ], and analysis [ 11 ]. Some of them propose novel micromixer designs [ 2 , 3 , 5 , 6 ], which include a slight modification of an existing micromixer [ 6 ].…”

“…The topics of the papers are focused on design of micromixers [ 2 , 3 , 4 , 5 , 6 , 7 , 9 , 12 , 13 ], fabrication [ 8 , 9 , 12 ], and analysis [ 11 ]. Some of them propose novel micromixer designs [ 2 , 3 , 5 , 6 ], which include a slight modification of an existing micromixer [ 6 ]. Most of them deal with passive micromixers, but two papers [ 5 , 11 ] report the studies on electrokinetic micromixers.…”