Investigation of the convective motion through a staggered herringbone micromixer at low Reynolds number flow

Hassell, David; Zimmerman, William B.

doi:10.1016/j.ces.2005.10.068

Cited by 71 publications

(41 citation statements)

References 6 publications

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“…5(c); η increases linearly at low groove depth ratios (d/h < 0.6), followed by an asymptotic increase at higher d/h ratios. This result parallels that of Stroock et al 18 along with previous numerical studies, 25,30,31 likely because η follows the same trends as the maximum shear rate (ν x /ν y ) concerning flow over patterned grooves. As with the asymptotic relationship seen in Fig.…”

Section: Optimization Of Groove Geometry With Depth Ratio D/hsupporting

confidence: 89%

“…30,31,33,34 To date there has been no study on the dependency of the groove geometries on the d/h ratio. figure 5, the optimized groove geometries may be fit to the asymptotic relationship:…”

Section: Optimization Of Groove Geometry With Depth Ratio D/hmentioning

confidence: 99%

“…Both Wang et al 30 and Hassell et al. 31 studied the effects of the groove depth to channel height ratio in SGM designs. Li et al 32 used a lattice Boltzmann method to study effects of the width fraction of the long arm and the number of grooves per half-cycle on SHM designs.…”

Section: Introductionmentioning

confidence: 99%

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Geometrical optimization of helical flow in grooved micromixers

Lynn

Dandy

2007

Lab Chip

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Owing to the enhancement of surface effects at the micro-scale, patterned grooves on a micro-channel floor remain a powerful method to induce helical flows within a pressure driven system. Although there have been a number of numerical studies on geometrical effects concerning fluid mixing within the staggered herringbone mixer, all have focused mainly on the groove angle and depth, two factors that contribute greatly to the magnitude of helical flow. Here we present a new geometrical factor that significantly affects the generation of helical flow over patterned grooves. By varying the ratio of the length of the grooves to the neighboring ridges, helical flow can be optimized for a given groove depth and channel aspect ratio, with up to 50% increases in transverse flow possible. A thorough numerical study of over 700 cases details the magnitude of helical flow over unsymmetrical patterned grooves in a slanted groove micro-mixer, where the optimized parameters for the slanted groove mixer can be translated to the staggered herringbone mixer. The optimized groove geometries are shown to have a large dependence on the channel aspect ratio, the groove depth ratio, and the ridge length.

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Section: Optimization Of Groove Geometry With Depth Ratio D/hsupporting

confidence: 89%

Section: Optimization Of Groove Geometry With Depth Ratio D/hmentioning

confidence: 99%

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Geometrical optimization of helical flow in grooved micromixers

Lynn

Dandy

2007

Lab Chip

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“…To characterize the mixing performance of the micromixers in order to better understand and design more efficient micromixers for different applications, a number of techniques, both experimentally [14][15][16][17][18] and theoretically [12,[19][20][21][22][23][24][25][26][27][28], have been employed. Particularly, CFD has been widely used to study the mixing behavior of micromixers in details.…”

Section: Open Accessmentioning

confidence: 99%

Evaluation of Floor-grooved Micromixers using Concentration-channel Length Profiles

Zhang

Yim

et al. 2010

Micromachines

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Abstract:We evaluated the dynamic micromixing performances in slanted groove micromixers (SGM) and staggered herringbone micromixers (SHM) and quantitatively compared their differences using concentration vs. channel length profiles obtained from numerical stimulations. It is found that faster and finer mixing took place in the SHM and the chaotic mixing was more effective at locations closer to the grooves; in comparison, slower and coarser mixing occurred throughout the whole channel of the SGM. Subsequently, the concentration profile-based characterization method was demonstrated in hybrid floor-grooved micromixers to study the interaction of SGM and SHM.

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“…Given the relatively straightforward fabrication that involves only a few lithographic steps and replica molding [8], several experimental studies have been aimed at improving the performance of this mixer by patterning structures on both the top and the bottom of the channel [21] or by adding oblique grooves on the side walls [22]. Moreover the geometrical simplicity of these designs makes them ideally suitable for computational fluid dynamics modelling through finite element analysis [23,24] and lattice Boltzmann approaches [25] and even simple analytical analysis [26]. Some of these studies have focused on determining the geometrical parameters that can affect the mixing performance, such as the groove depth to channel height ratio [27], the number of grooves per half cycle [25], the width of the grooves [28], the ratio between the width of the grooves with respect to the neighbouring ridges [29], or the ratio of the long arm to the short arm of the grooves [30].…”

Section: -P1mentioning

confidence: 99%

Assessment of mixing in passive microchannels with fractal surface patterning

Fodor

Itomlenskis

Kaufman

2009

Eur. Phys. J. Appl. Phys.

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Abstract. We explore numerically the feasibility of enhancing the mixing capability of microchannels by employing the Weierstrass fractal function to generate a pattern of V-shaped ridges on the channel floor. Motivated by experimental limitations such as the finite resolution (∼10 µm) associated with rapid prototyping through soft lithography techniques, we study the influence on the quality of mixing of having finite width ridges. The mixing capability of the designs studied is evaluated using an entropic measure and the designs are optimized with respect to: the distances between the ridges and the position range of their tip along the width of the channels. The results are evaluated with respect to the benchmarks established by the very successful staggered herring bone (SHB) design. We find that the use of a non periodic protocol to generate the geometry of the bottom surface of the microchannels can lead to consistently larger entropic mixing indices than in cyclic structures. Furthermore, since the optimization curves (mixing index vs. geometric parameters) are broader at the maximum for fractal microchannels than for their SHB counterparts, the microchannel designs using the Weierstrass fractal function are less sensitive to experimental uncertainties. PACS

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Investigation of the convective motion through a staggered herringbone micromixer at low Reynolds number flow

Cited by 71 publications

References 6 publications

Geometrical optimization of helical flow in grooved micromixers

Geometrical optimization of helical flow in grooved micromixers

Evaluation of Floor-grooved Micromixers using Concentration-channel Length Profiles

Assessment of mixing in passive microchannels with fractal surface patterning

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