Toward the Next Generation of Passive Micromixers: A Novel 3-D Design Approach

Abstract

Passive micromixers are miniaturized instruments that are used to mix fluids in microfluidic systems. In microchannels, combination of laminar flows and small diffusion constants of mixing liquids produce a difficult mixing environment. In particular, in very low Reynolds number flows, e.g., Re < 10, diffusive mixing cannot be promoted unless a large interfacial area is formed between the fluids to be mixed. Therefore, the mixing distance increases substantially due to a slow diffusion process that governs fluid mixing. In this article, a novel 3-D passive micromixer design is developed to improve fluid mixing over a short distance. Computational Fluid Dynamics (CFD) simulations are used to investigate the performance of the micromixer numerically. The circular-shaped fluid overlapping (CSFO) micromixer design proposed is examined in several fluid flow, diffusivity, and injection conditions. The outcomes show that the CSFO geometry develops a large interfacial area between the fluid bodies. Thus, fluid mixing is accelerated in vertical and/or horizontal directions depending on the injection type applied. For the smallest molecular diffusion constant tested, the CSFO micromixer design provides more than 90% mixing efficiency in a distance between 260 and 470 µm. The maximum pressure drop in the micromixer is found to be less than 1.4 kPa in the highest flow conditioned examined.

Construction of a desirable hyperbolic microfluidic chip for ultrasensitive determination of PCT based on chemiluminescence

“…In contrast, passive micromixers only use the inertial forces caused by the fluid flow and microchannel structure to achieve mixing, which is simple, easy to manufacture, and highly integrated, and can better accommodate analytical instruments. [18][19][20] It can be noted that bending micromixers use Dean vortices as a typical passive mixer, and lateral Dean flows in microchannels to enhance fluid mixing. Mashaei et al constructed a new chaotic micro-mixer consisting of four consecutive non-planar arrangements of quadrant cells to investigate its flow characteristics and mixing efficiency numerically.…”

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.…”

“…Most of them deal with passive micromixers, but two papers [ 5 , 11 ] report the studies on electrokinetic micromixers. Fully three-dimensional (3D) micromixers were investigated in some cases [ 2 , 3 , 4 , 13 ]. Hossain et al [ 4 ] applied optimization techniques to the design of a 3D micromixer.…”

“…Different methods have been applied to the analysis of mixing. Most of the works used only computational fluid dynamics (CFD) for the analysis [ 2 , 3 , 4 , 5 , 6 , 10 , 13 ]. However, some of the works employed experimental analysis [ 8 , 9 ] or both experimental and CFD analyses [ 7 , 12 ].…”