Rapid multivortex mixing in an alternately formed contraction-expansion array microchannel

Lee, Myung Gwon; Choi, Sungyoung; Park, Je‐Kyun

doi:10.1007/s10544-010-9456-8

Cited by 29 publications

(13 citation statements)

References 28 publications

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“…Two kinds of secondary flows can be created in CEA microchannel including circulating vortex in horizontal plane, due to the detachment of fluid boundary layer in the channel expansion area at a large inertia [38][39][40], and counter-rotating flow in cross-sectional plane [36], produced by radial pressure gradient in the downstream of cavity contraction area, similar as the Dean flow in curved channel. Circulating vortex in horizontal plane was investigated extensively to trap specific bio-particles (such as CTCs) from mainstream according to their sizes [39][40], as shown in figure 1(b).…”

Section: Introductionmentioning

confidence: 99%

Inertial focusing in a straight channel with asymmetrical expansion–contraction cavity arrays using two secondary flows

Zhang

et al. 2013

J. Micromech. Microeng.

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G. (2013). Inertial focusing in a straight channel with asymmetrical expansion-contraction cavity arrays using two secondary flows. Journal of Micromechanics and Microengineering, 23 (8), 1-13. Inertial focusing in a straight channel with asymmetrical expansioncontraction cavity arrays using two secondary flows AbstractThe focusing of particles has a variety of applications in industry and biomedicine, including wastewater purification, fermentation filtration, and pathogen detection in flow cytometry, etc. In this paper a novel inertial microfluidic device using two secondary flows to focus particles is presented. The geometry of the proposed microfluidic channel is a simple straight channel with asymmetrically patterned triangular expansion-contraction cavity arrays. Three different focusing patterns were observed under different flow conditions: (1) a single focusing streak on the cavity side; (2) double focusing streaks on both sides; (3) half of the particles were focused on the opposite side of the cavity, while the other particles were trapped by a horizontal vortex in the cavity. The focusing performance was studied comprehensively up to flow rates of 700 μl min−1. The focusing mechanism was investigated by analysing the balance of forces between the inertial lift forces and secondary flow drag in the cross section. The influence of particle size and cavity geometry on the focusing performance was also studied. The experimental results showed that more precise focusing could be obtained with large particles, some of which even showed a single-particle focusing streak in the horizontal plane. Meanwhile, the focusing patterns and their working conditions could be adjusted by the geometry of the cavity. This novel inertial microfluidic device could offer a continuous, sheathless, and high-throughput performance, which can be potentially applied to high-speed flow cytometry or the extraction of blood cells. (1) single focusing streak on cavity side; (2) double focusing streaks on both sides; (3) half of particles focused on the opposite side of cavity, and other particles trapped by horizontal vortex in cavity. The focusing performance was studied comprehensively up to the flow rates of 700 µl min -1 . The focusing mechanism was investigated by analyzing force balance between inertial lift forces and secondary flow drag in the cross section.The influence of particle size and cavity geometry on the focusing performance was also studied. Experimental results showed that a more pronounced focusing performance can be obtained with large particles, which even showed a single-particle focusing streak in horizontal plane. Meanwhile, focusing patterns and their working conditions were adjustable by the geometry of cavity. The novel inertial microfluidic device was capable of offering a continuous, sheathless, and high-throughput performance, which can be potentially applied to highspeed flow cytometry or extraction of blood cells.

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Section: Introductionmentioning

confidence: 99%

Inertial focusing in a straight channel with asymmetrical expansion–contraction cavity arrays using two secondary flows

Zhang

et al. 2013

J. Micromech. Microeng.

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“…Comparison of micromixers based on chaotic advection in three-dimensional (3D) structures and those designs based on planar structures shows that the 3D structures are better at mixing, but their fabrication requires either multi-step lithography or aligned assembly of multiple layers (Chen and Meiners 2004;Liu et al 2000;Stroock et al 2002). In planar micromixers, effective mixing can be obtained by lamination (Abonnenc et al 2009;Hessel et al 2003;Wu and Nguyen 2005), hydrodynamic focusing (Knight et al 1998), flow impinging (Bothe et al 2006), Dean vortices (Jiang et al 2004;Yi and Bau 2003), separation vortices (Bhagat et al 2007;Chung et al 2008;Wang et al 2002) or a combination of the above strategies (Lee et al 2010;Sudarsan and Ugaz 2006;Tsai and Wu 2011).…”

Section: Introductionmentioning

confidence: 99%

Multidirectional vortices mixing in three-stream micromixers with two inlets

Tsai

2012

Microsyst Technol

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In this work, we design, fabricate and compare three types of three-stream curved-straight-curved (CSC) micromixers, including the full three-stream (FTS) CSC micromixer, the CSC microchannel with internal side-wall injection and the CSC microchannel with external sidewall injection. In the three-stream CSC micromixers, there is a core stream sandwiched by two cladding streams into the CSC channel with baffles from two inlets. The sandwiched structure of streams and the multidirectional vortices due to flow separation and channel curvature contribute together to enhance mixing. We examine fluid mixing in the proposed micromixers by numerical simulation and using confocal spectral microscope imaging system. The present results show that the mixing efficiency increases without increasing the pressure applied much by the channel structure forming the sandwiched structure of streams. Besides, it is found that the FTS CSC micromixer is the preferable one among the micromixers considered.

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“…Through this way, a chaotic flow is induced, which enhances the mixing efficiency. 40 In most of the previous passive mixers, where vortices play a key role in increasing the mixing efficiency, vortex regions were confined to a specific segment of the channel 43,44 while in the micromixers presented in this work, mixing process occurs throughout the structure. Moreover, in designs where the Dean vortices are responsible for increasing the efficiency, the channel length was normally limited due to the lack of fabrication space on a 2D plane.…”

Section: Design Of 3d Micromixersmentioning

confidence: 87%

An easily fabricated three-dimensional threaded lemniscate-shaped micromixer for a wide range of flow rates

Rafeie

Welleweerd

Hassanzadeh-Barforoushi

et al. 2017

Biomicrofluidics

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Mixing fluid samples or reactants is a paramount function in the fields of micro total analysis system (lTAS) and microchemical processing. However, rapid and efficient fluid mixing is difficult to achieve inside microchannels because of the difficulty of diffusive mass transfer in the laminar regime of the typical microfluidic flows. It has been well recorded that the mixing efficiency can be boosted by migrating from two-dimensional (2D) to three-dimensional (3D) geometries. Although several 3D chaotic mixers have been designed, most of them offer a high mixing efficiency only in a very limited range of Reynolds numbers (Re). In this work, we developed a 3D fine-threaded lemniscate-shaped micromixer whose maximum numerical and empirical efficiency is around 97% and 93%, respectively, and maintains its high performance (i.e., >90%) over a wide range of 1 < Re < 1000 which meets the requirements of both the lTAS and microchemical process applications. The 3D micromixer was designed based on two distinct mixing strategies, namely, the inducing of chaotic advection by the presence of Dean flow and diffusive mixing through thread-like grooves around the curved body of the mixers. First, a set of numerical simulations was performed to study the physics of the flow and to determine the essential geometrical parameters of the mixers. Second, a simple and cost-effective method was exploited to fabricate the convoluted structure of the micromixers through the removal of a 3D-printed wax structure from a block of cured polydimethylsiloxane. Finally, the fabricated mixers with different threads were tested using a fluorescent microscope demonstrating a good agreement with the results of the numerical simulation. We envisage that the strategy used in this work would expand the scope of the micromixer technology by broadening the range of efficient working flow rate and providing an easy way to the fabrication of 3D convoluted microstructures. Published by AIP Publishing.

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Rapid multivortex mixing in an alternately formed contraction-expansion array microchannel

Cited by 29 publications

References 28 publications

Inertial focusing in a straight channel with asymmetrical expansion–contraction cavity arrays using two secondary flows

Inertial focusing in a straight channel with asymmetrical expansion–contraction cavity arrays using two secondary flows

Multidirectional vortices mixing in three-stream micromixers with two inlets

An easily fabricated three-dimensional threaded lemniscate-shaped micromixer for a wide range of flow rates

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