Mixing behavior of the rhombic micromixers over a wide Reynolds number range using Taguchi method and 3D numerical simulations

Abstract

A planar micromixer with rhombic microchannels and a converging-diverging element has been systematically investigated by the Taguchi method, CFD-ACE simulations and experiments. To reduce the footprint and extend the operation range of Reynolds number, Taguchi method was used to numerically study the performance of the micromixer in a L(9) orthogonal array. Mixing efficiency is prominently influenced by geometrical parameters and Reynolds number (Re). The four factors in a L(9) orthogonal array are number of rhombi, turning angle, width of the rhombic channel and width of the throat. The degree of sensitivity by Taguchi method can be ranked as: Number of rhombi > Width of the rhombic channel > Width of the throat > Turning angle of the rhombic channel. Increasing the number of rhombi, reducing the width of the rhombic channel and throat and lowering the turning angle resulted in better fluid mixing efficiency. The optimal design of the micromixer in simulations indicates over 90% mixing efficiency at both Re > or = 80 and Re < or = 0.1. Experimental results in the optimal simulations are consistent with the simulated one. This planar rhombic micromixer has simplified the complex fabrication process of the multi-layer or three-dimensional micromixers and improved the performance of a previous rhombic micromixer at a reduced footprint and lower Re.

A novel micromixer with multimixing mechanisms for high mixing efficiency at low Reynolds number

“…Smaller value of standard deviation means that the mixture is more homogenous and vice versa. The mixing efficiency is then calculated as in (5). Consequently, the value of mixing efficiency is 1 for completely mixing (100%) and is 0 for no mixing (0%).…”

“…The authors in [5,6] propose planar passive micromixers with rhombic microchannels. These micromixers exploit the equal spitting and recombining of laminar flows to enhance the mixing efficiency.…”

Diffusion and convection mixing of non‐Newtonian liquids in an optimized micromixer

“…[15] Nimafar et al [4] carried out an experimental study to compare three SAR-type micromixers. Chung et al, [18] using simulations and experiments, investigated a planar rhombic micromixer with a converging-diverging element. They concluded that mixing is accomplished more quickly in their SAR design compared to T-and O-mixers at all flow rates.…”

Passive micromixers with dual helical channels

“…Although active methods can achieve fast and effective mixing, they simultaneously complicate the fabricating process of microfluidic systems and need complex operations during the assay process [6]. Two passive micromixing concepts, namely split-recombine multilamination and chaotic advection, have been applied as passive micromixers [7,8]. Such passive micromixers are designed to promote an efficient diffusion with complex multilayer or three-dimensional (3D) microfluidic channels, either by increasing the interfacial area between fluids or by decreasing the distance over which diffusion takes place.…”