Asymmetrical Split-and-Recombine Micromixer with Baffles

Raza, Wasim; Kim, Kwang‐Yong

doi:10.3390/mi10120844

Cited by 25 publications

(24 citation statements)

References 26 publications

(49 reference statements)

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“…Due to the fluid momentum mismatch between the near wall and the central area in these platforms, Dean vortex or Dean-like secondary vortex flows can be generated in the main channel section by a radial pressure gradient [ 13 ]. Besides the formation of a secondary counter-rotating vortex flow, channels with disturbance obstacles can also generate a horizontal micro-vortex under a high flow rate because of the detachment of the boundary layer, and have been employed in fluid and particle manipulations [ 25 , 26 , 27 , 28 , 29 , 30 ]. However, such unique channel designs often face the challenge of high microchannel production and cost increase because of the standard soft lithography and stereolithography technology [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Multivortex Regulation in Curved Microchannels with Ultra-Low-Aspect-Ratio

et al. 2021

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The field of inertial microfluidics has been significantly advanced in terms of application to fluid manipulation for biological analysis, materials synthesis, and chemical process control. Because of their superior benefits such as high-throughput, simplicity, and accurate manipulation, inertial microfluidics designs incorporating channel geometries generating Dean vortexes and helical vortexes have been studied extensively. However, existing technologies have not been studied by designing low-aspect-ratio microchannels to produce multi-vortexes. In this study, an inertial microfluidic device was developed, allowing the generation and regulation of the Dean vortex and helical vortex through the introduction of micro-obstacles in a semicircular microchannel with ultra-low aspect ratio. Multi-vortex formations in the vertical and horizontal planes of four dimension-confined curved channels were analyzed at different flow rates. Moreover, the regulation mechanisms of the multi-vortex were studied systematically by altering the micro-obstacle length and channel height. Through numerical simulation, the regulation of dimensional confinement in the microchannel is verified to induce the Dean vortex and helical vortex with different magnitudes and distributions. The results provide insights into the geometry-induced secondary flow mechanism, which can inspire simple and easily built planar 2D microchannel systems with low-aspect-ratio design with application in fluid manipulations for chemical engineering and bioengineering.

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Section: Introductionmentioning

confidence: 99%

Numerical Study of Multivortex Regulation in Curved Microchannels with Ultra-Low-Aspect-Ratio

et al. 2021

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“…They showed that multi-directional vortices and the Dean vortex enhanced the mixing performance of their micro-mixer. Raza et al [ 27 ] proposed a SAR mixing unit combined with baffles in a curved channel, and analyzed numerically its mixing performance. They showed that its mixing performance is better than their earlier version of SAR micro-mixer.…”

Section: Resultsmentioning

confidence: 99%

“…For example, Sheu et al [ 26 ] designed a SAR with tapered curved micro-channels that allowed the introduction of Dean vortex flows by the centrifugal effects. Raza et al [ 27 ] proposed the unbalanced SAR micro-mixer combined with baffles in curved micro-channels that improved the mixing performance of similar shaped SAR micro-mixers. Bazaz et al [ 28 ] proposed a micro-mixer combining various mixing units such as teardrop, obstruction, nozzle & pillar, and Tesla.…”

Section: Introductionmentioning

confidence: 99%

“…They used a commercial software, FLUENT to obtain detailed flow data in micro-channels. Raza et al [ 27 ] studied the mixing performance of an asymmetrical split and recombine micro-mixer with baffles using CFX15.0. The numerical results were used to evaluate quantitatively the mixing performance of their micro-mixer, in comparison with others.…”

Section: Introductionmentioning

confidence: 99%

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Mixing Performance of a Cross-Channel Split-and-Recombine Micro-Mixer Combined with Mixing Cell

Juraeva

Kang

2020

Micromachines

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A new cross-channel split-and-recombine (CC-SAR) micro-mixer was proposed, and its performance was demonstrated numerically. A numerical study was carried out over a wide range of volume flow rates from 3.1 μL/min to 826.8 μL/min. The corresponding Reynolds number ranges from 0.3 to 80. The present micro-mixer consists of four mixing units. Each mixing unit is constructed by combining one split-and-recombine (SAR) unit with a mixing cell. The mixing performance was analyzed in terms of the degree of mixing and relative mixing cost. All numerical results show that the present micro-mixer performs better than other micro-mixers based on SARs over a wide range of volume flow rate. The mixing enhancement is realized by a particular motion of vortex flow: the Dean vortex in the circular sub-channel and another vortex inside the mixing cell. The two vortex flows are generated on the different planes perpendicular to each other. They cause the two fluids to change their relative position as the fluids flow into the circular sub-channel of the SAR, eventually promoting violent mixing. High vorticity in the mixing cell elongates the flow interface between two fluids, and promotes mixing in the flow regime of molecular diffusion dominance.

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“…Generally, these methods can be divided into two categories: active methods and passive methods [4]. Passive methods usually utilize various geometries [5–17] of microchannels and different shapes of obstacles [18–23] or grooves [24–27] placed in microchannels to disturb the laminar flow for vortex formation. Passive methods do not need external energy sources, but the channels of such methods usually need to be designed with complex structures, thereby increasing the fabrication difficulty.…”

Section: Introductionmentioning

confidence: 99%

Electrokinetic‐vortex formation near a two‐part cylinder with same‐sign zeta potentials in a straight microchannel

2020

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Vortex formation near a two-part cylinder with zeta potentials of different values but the same sign under an external DC electric field is numerically investigated in this paper. The cylinder, inserted in a straight microchannel filled with an aqueous solution, is composed of an upstream part and a downstream part. When a DC electric field is applied in the channel, under certain conditions, the vortex will form near the cylinder due to the different velocities of electroosmotic flow generated on the cylinder surface. The numerical results reveal that the larger the velocity difference of electroosmotic flow generated on the two-part cylinder and the smaller the channel width, the more conducive to vortex formation in the channel. In addition, if the zeta potential ratios of cylinder downstream part to upstream part and channel wall to cylinder upstream part are unchanged, the DC electric field strength and the zeta potential value do not affect the pattern of vortices formed in the channel. This study provides a way for vortex formation in microchannels and has the potential application in microfluidic devices.

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Asymmetrical Split-and-Recombine Micromixer with Baffles

Cited by 25 publications

References 26 publications

Numerical Study of Multivortex Regulation in Curved Microchannels with Ultra-Low-Aspect-Ratio

Numerical Study of Multivortex Regulation in Curved Microchannels with Ultra-Low-Aspect-Ratio

Mixing Performance of a Cross-Channel Split-and-Recombine Micro-Mixer Combined with Mixing Cell

Electrokinetic‐vortex formation near a two‐part cylinder with same‐sign zeta potentials in a straight microchannel

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