A Numerical Research of Herringbone Passive Mixer at Low Reynold Number Regime

Abstract

Passive mixing based on microfluidics has won its popularity for its unique advantage, including easier operation, more efficient mixing performance and higher access to high integrity. The time-scale and performance of mixing process are usually characterized by mixing quality, which has been remarkably improved due to the introduction of chaos theory into passive micro mixers. In this paper, we focus on the research of mixing phenomenon at extremely low Reynold number (Re) regime in a chaotic herringbone mixer. Three-dimensional (3D) modeling has been carried out using computational fluid dynamics (CFD) method, to simulate the chaos-enhanced advection diffusion process. Static mixing processes using pressure driven and electric field driven modes are investigated. Based on the simulation results, the effects of flow field and herringbone pattern are theoretically studied and compared. Both in pressure driven flow and electro-osmotic flow (EOF), the mixing performance is improved with a lower flow rate. Moreover, it is noted that with a same total flow rate, mixing performance is better in EOF than pressure driven flow, which is mainly due to the difference in flow field distribution of pressure driven flow and EOF.

Novel 3-D T-Shaped Passive Micromixer Design with Helicoidal Flows

“…In addition, mixing efficiencies reported (e.g., see the References [38,39,[41][42][43]) are still far behind an acceptable threshold value (e.g., 80% [29]). Similar consequences are also seen in grooved-and obstruction-type passive micromixer geometries (e.g., see the References [13,32,36,44]). In this study, we propose a simple, yet effective and novel micromixer design in which all the aforementioned factors are substantially minimized.…”

Microfluidic Mixer with Automated Electrode Switching for Sensing Applications

“…In this case, the microchannel mold is sketched using Autodesk Inventor software and consists of a rectangular microchannel (500 µm wide) with three cycles of SHM, as shown in Figure 1a. Since some factors strongly affect the mixing efficiency in SHM structures, especially the groove depth [27], the SHM features for the mold sketched in this scenario ( Figure 1b) are chosen based on the geometry proportions obtained from the literature [20,[27][28][29]. A Y-shaped microchannel is designed to accommodate two electrodes before the mixer and one electrode after that.…”

Editorial for the Special Issue on Passive Micromixers

“…The important areas being focused upon are the numerical and experimental analyses of flow and mixing in different micromixers [1,2,3,4,5], optimization [6,7,8], and fabrication of micromixers [9]. In the review paper [10], recent developments in both active and passive micromixers are summarized and discussed.…”

“…Computational fluid dynamics (CFD) analysis of flow and mixing is seen as an important tool in designing passive micromixers in eight research articles [1,2,3,4,5,6,7,8]. Javaid et al [1] proposed a serpentine-shaped micromixer with sinusoidal walls and conducted a CFD analysis using COMSOL Multiphysics software.…”

“…The design is promising as it can efficiently increase the mixing for T-junction micromixers. Wang et al [4] carried out CFD analysis of a herringbone passive micromixer for pressure-driven and electro-osmotic flow. A good mixing performance was observed at low flow rates for both flow situations.…”