Formation of recirculation zones in a sudden expansion microchannel with a rectangular block structure over a wide Reynolds number range

Tsai, Chien Hsiung; Yeh, Cheng Peng; Lin, Che-Hsin; Yang, Ruey-Jen; Fu, Lung-Ming

doi:10.1007/s10404-011-0864-8

Cited by 18 publications

(5 citation statements)

References 41 publications

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“…Embedding structures within a flow channel has been used to generate passive microvortices —thereby creating highly efficient micromixers, 68 — to form recirculation zones in suddenly expanding microchannels, 69 or to generate cell-free zones for blood plasma isolation. 70 These structures operate on the principle that the flow is disturbed by these structures, leading to the creation of low-pressure zones and microvortices that exert forces on the fluid or cells.…”

Section: Resultsmentioning

confidence: 99%

Portable platform for leukocyte extraction from blood using sheath-free microfluidic DLD

Chavez-Pineda,

Rodriguez-Moncayo,

Gonzalez-Suarez

et al. 2024

Lab Chip

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Section: Resultsmentioning

confidence: 99%

Portable platform for leukocyte extraction from blood using sheath-free microfluidic DLD

Chavez-Pineda,

Rodriguez-Moncayo,

Gonzalez-Suarez

et al. 2024

Lab Chip

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“…Passive microvortices are created by channel geometries like sudden expansions in microscale channels [7,12,15,18,19], cylindrical microcavities [35], trapezoidal side chambers [14], microbifurcations [28], embedded obstacles inside the flow channel [21,36,37], two counterflowing liquid streams [9] or at the boundary layer between sheath and center stream [22].…”

Section: Introductionmentioning

confidence: 99%

Microfluidic Vortex Enhancement for on-Chip Sample Preparation

et al. 2015

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In the past decade a large amount of analysis techniques have been scaled down to the microfluidic level. However, in many cases the necessary sample preparation, such as separation, mixing and concentration, remains to be performed off-chip. This represents a major hurdle for the introduction of miniaturized sample-in/answer-out systems, preventing the exploitation of microfluidic's potential for small, rapid and accurate diagnostic products. New flow engineering methods are required to address this hitherto insufficiently studied aspect. One microfluidic tool that can be used to miniaturize and integrate sample preparation procedures are microvortices. They have been successfully applied as microcentrifuges, mixers, particle separators, to name but a few. In this work, we utilize a novel corner structure at a sudden channel expansion of a microfluidic chip to enhance the formation of a microvortex. For a maximum area of the microvortex, both chip geometry and corner structure were optimized with a computational fluid dynamic (CFD) model. Fluorescent particle trace measurements with the optimized design prove Micromachines 2015, 6 240 that the corner structure increases the size of the vortex. Furthermore, vortices are induced by the corner structure at low flow rates while no recirculation is observed without a corner structure. Finally, successful separation of plasma from human blood was accomplished, demonstrating a potential application for clinical sample preparation. The extracted plasma was characterized by a flow cytometer and compared to plasma obtained from a standard benchtop centrifuge and from chips without a corner structure.

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“…The velocity distribution and streamlines were obtained through the experiments and commercial software FLUENT. Tsai et al [13][14][15] focused on the formation of recirculation zones in a sudden expansion microchannel. They found that Reynolds number and aspect ratio are both influential factors for flow patterns in microchannels.…”

Section: Introductionmentioning

confidence: 99%

Lattice Boltzmann numerical simulation and experimental research of dynamic flow in an expansion-contraction microchannel

et al. 2013

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This paper applies the lattice Boltzmann method (LBM) to a 3D simulation of micro flows in an expansion-contraction microchannel. We investigate the flow field under various inlet flow rates and cavity structures, and then systematically study the flow features of the vortex and Dean flow in this channel. Vortex formation analysis demonstrates that there is no observable vortex generated when the inlet flow rate is low enough. As the inlet flow rate increases, a small vortex first appears near the inlet, and then this vortex region will keep expanding until it fully occupies the cavity. A smaller cavity width may result in a larger vortex but the vortex is less influenced by cavity length. The Dean flow features at the outlet become more apparent with increasing inlet flow rate and more recirculation regions can be observed in the cross-section under over high inlet flow rate. In order to support the simulation results, some experimental processes are conducted successfully. It validates that the applied model can accurately characterize the flow in the microchannel. Results of simulations and experiments in this paper provide insights into the design and operation of microfluidic systems for particle/cell manipulation.

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Formation of recirculation zones in a sudden expansion microchannel with a rectangular block structure over a wide Reynolds number range

Cited by 18 publications

References 41 publications

Portable platform for leukocyte extraction from blood using sheath-free microfluidic DLD

Portable platform for leukocyte extraction from blood using sheath-free microfluidic DLD

Microfluidic Vortex Enhancement for on-Chip Sample Preparation

Lattice Boltzmann numerical simulation and experimental research of dynamic flow in an expansion-contraction microchannel

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