Investigations into mixing of fluids in microchannels with lateral obstructions

Sahu, Pankaj; Golia, Aakash; Sen, A. K.

doi:10.1007/s00542-012-1617-7

Cited by 25 publications

(13 citation statements)

References 25 publications

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“…Recently, computational fluid dynamics (CFD) has become very popular technique to analyze the mixing and fluid flow in micromixers. In recent years, many investigations have been performed to improve the mixing in a variety of passive micromixers; T-type micromixer (Gobby et al 2001 ) and Y-type micromixer (Sahu et al 2012 ), serpentine micromixers (Beebe et al 2001 ; Hossain et al 2009 ; Ansari and Kim 2009 ; Sahu et al 2013 ), split-and-recombinination (SAR) micromixers (Lee and Lee 2008 ; Viktorov and Nimafar 2013 ; Nimafar et al 2012a , b ; Hossain and Kim 2014 ), patterned grooves micromixers (Ansari and Kim 2007 ; Hossain et al 2010a , b ), etc. It was exposed that shifting the inlet direction in a T-type micromixer did not appreciably improve the mixing performance (Gobby et al 2001 ).…”

Section: Introductionmentioning

confidence: 99%

Parametric investigation on mixing in a micromixer with two-layer crossing channels

Hossain

Kim

2016

SpringerPlus

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This work presents a parametric investigation on flow and mixing in a chaotic micromixer consisting of two-layer crossing channels proposed by Xia et al. (Lab Chip 5: 748–755, 2005). The flow and mixing performance were numerically analyzed using commercially available software ANSYS CFX-15.0, which solves the Navier–Stokes and mass conservation equations with a diffusion–convection model in a Reynolds number range from 0.2 to 40. A mixing index based on the variance of the mass fraction of the mixture was employed to evaluate the mixing performance of the micromixer. The flow structure in the channel was also investigated to identify the relationship with mixing performance. The mixing performance and pressure-drop were evaluated with two dimensionless geometric parameters, i.e., ratios of the sub-channel width to the main channel width and the channels depth to the main channel width. The results revealed that the mixing index at the exit of the micromixer increases with increase in the channel depth-to-width ratio, but decreases with increase in the sub-channel width to main channel width ratio. And, it was found that the mixing index could be increased up to 0.90 with variations of the geometric parameters at Re = 0.2, and the pressure drop was very sensitive to the geometric parameters.

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Section: Introductionmentioning

confidence: 99%

Parametric investigation on mixing in a micromixer with two-layer crossing channels

Hossain

Kim

2016

SpringerPlus

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“…1 g is inversely proportional to the sample concentration ( Fig. The initial spacing between objects in region 1 i.e.…”

Section: Spacing Control Of Objectsmentioning

confidence: 99%

“…[1][2][3][4] Development of lab on chip (LOC) devices as point-ofcare diagnostic tools is one of the pivotal applications of microfluidics. [1][2][3][4] Development of lab on chip (LOC) devices as point-ofcare diagnostic tools is one of the pivotal applications of microfluidics.…”

Section: Introductionmentioning

confidence: 99%

“…Microfluidics, which concerns design, fabrication and experiments of miniaturized fluidic systems, has a number of applications in biomedicine, diagnostics and chemical analysis. [1][2][3][4] The development of lab-on-a-chip (LOC) devices as point-ofcare diagnostic tools is one of the pivotal applications of microfluidics. 5 A typical LOC device has various functional modules including sample preparation and transportation module, separation module, and detection and analysis module.…”

Section: Introductionmentioning

confidence: 99%

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A microfluidic device with focusing and spacing control for resistance-based sorting of droplets and cells

et al. 2015

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This paper reports a novel hydrodynamic technique for sorting of droplets and cells based on size and deformability. The device comprises two modules: a focusing and spacing control module and a sorting module. The focusing and spacing control module enables focusing of objects present in a sample onto one of the side walls of a channel with controlled spacing between them using a sheath fluid. A 3D analytical model is developed to predict the sheath-to-sample flow rate ratio required to facilitate single-file focusing and maintain the required spacing between a pair of adjacent objects. Experiments are performed to demonstrate focusing and spacing control of droplets (size 5-40 μm) and cells (HL60, size 10-25 μm). The model predictions compare well with experimental data in terms of focusing and spacing control within 9%. In the sorting module, the main channel splits into two branch channels (straight and side branches) with the flow into these two channels separated by a "dividing streamline". A sensing channel and a bypass channel control the shifting of the dividing streamline depending on the object size and deformability. While resistance offered by individual droplets of different sizes has been studied in our previous work (P. Sajeesh, M. Doble and A. K. Sen, Biomicrofluidics, 2014, 8, 1-23), here we present resistance of individual cells (HL60) as a function of size. A theoretical model is developed and used for the design of the sorter. Experiments are performed for size-based sorting of droplets (sizes 25 and 40 μm, 10 and 15 μm) and HL60 cells (sizes 11 μm and 19 μm) and deformability-based sorting of droplets (size 10 ± 1.0 μm) and polystyrene microbeads (size 10 ± 0.2 μm). The performance of the device for size- and deformability-based sorting is characterized in terms of sorting efficiency. The proposed device could be potentially used as a diagnostic tool for sorting of larger tumour cells from smaller leukocytes.

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“…When the channel depth of a micromixer is scaled down to nanometer, in addition to the omnipresence of laminar flow conditions, as the aspect ratio (i.e., the height to width ratio) decreases, the effect of wall shear increases rapidly, leading to poor mixing. 13 On the other hand, an important feature of nanofluidics is the extremely large surface-to-volume ratio in nanochannel and the surface property becomes crucial comparing to microchannel. Therefore, the effect of channel walls becomes very significant and should be taken into account in nanofluidic mixing.…”

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confidence: 99%