Analysis of passive microfluidic mixers incorporating 2D and 3D baffle geometries fabricated using an excimer laser

Abstract

We present new passive microfluidic mixing structures based on 2D and 3D geometries. The primary mechanism of mixing in these devices is based on chaotic advection. The mixers which incorporate 3D structures introduce transverse flow rotation greatly enhancing performance. Simulations and experimental tests were performed over a Reynolds number (Re) range from 0.1 to 20 and showed good agreement. At an Re of 0.1, 90% mixing was achieved in a path length of 32 and 7 mm, for the 2D and 3D geometrical mixers, respectively. This represents an improvement in performance over a standard T-mixer of 20% for the 2D mixer and 82.5% for the 3D mixer. An inflection point in the mixing efficiency was observed for both mixer types around an Re of 1. The devices were fabricated on a polymethylmethacrylate (PMMA) substrate, using an excimer laser beam incorporating an intelligent pinhole mask. Initially, structures were developed off-line using a laser simulation tool. A design-of-experiments (DOE) approach along with computational fluid dynamic (CFD) analysis was used to optimise mixing element geometry. This precursor to the fabrication step greatly reduces the time between the design stage and device realisation.

An efficient planar accordion-shaped micromixer: from biochemical mixing to biological application

“…(1) ). This is a considerable improvement compared to the results of former works (11.0 mm 35 and 32.0 mm 29 ), where a higher diffusion coefficient, D = 1 × 10 −10 m 2 /s, was taken into consideration. Clearly, this mixing efficiency and length can be further improved by considering the same diffusion coefficient.…”

“…We numerically investigated the influence of the geometrical characteristics of the design on the mixing performance over a wide range of flow conditions. The performance of the most efficient design was experimentally investigated by means of fluorescence microscopy for a range of diffusion coefficients, 10 −12 < D < 10 −11 m 2 /s, and compared with the previous works 17 30 35 36 . Then, we demonstrated the potential diagnostic value of the micromixer by testing its capability for Red Blood Cells (RBC) lysis.…”

Bubble-based acoustic micropropulsors: active surfaces and mixers

“…Most theoretical studies of mixing use detailed numerical simulations 11,42 or scaling arguments 19,21 . Here we present an alternative approach, namely a numerical method applied to a simplified mixer-channel setup.…”

Numerical analysis of lamination effect in a vortex micro T-mixer with non-aligned inputs

“…The results showed that in the Reynolds number range of 10-50 with the increase of sinusoidal wave amplitude the mixing performance increases, but at the Re = 70 the increase of sinusoidal wave amplitude has not affected the mixing performance. Conlisk and O'Connor [10] studied both numerically and experimentally the mixing performance of the mixer in two and three dimensional states. The Reynolds number varied in the range of 0.1 ≤ Re ≤ 20.…”