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

Hossain, Shakhawat; Kim, Kwang‐Yong

doi:10.1186/s40064-016-2477-x

Cited by 13 publications

(14 citation statements)

References 37 publications

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“…As can be seen from Table 3, when Re < 10, all the mixers could work. When Re < 1, more than half of the mixers worked (the mixers in references [11,12,13,14,24,26] and the mixer used in this paper), which indicated that these devices were suitable for laminar flow mixing. For all the mixers, the maximum mixing length was no more than 13 mm [12], while the minimum mixing length was 2.75 mm [11], which indicated that the structure size was suitable for integration in μTASs.…”

Section: Resultsmentioning

confidence: 78%

“…The mixing index of each mixer exceeded 70%. However, for seven mixers, the mixing index exceeded 80% (the mixers in references [11,13,14,15,24,26], and for three mixers, it exceeded 90%, namely the GSMMT (grooves staggered in the upper and lower layers at the midstream positions) [15] ( α = 90%, when Re = 96), the 3D Tesla [13] ( α = 94%, when Re = 1), and the 3D HT used in the present study ( α simulation = 96.4%, α test = 91.75%, when Re = 10). However, compared to the 3D HT mixer, the GSMMT structure required a higher Re, while the 3D Tesla needed more mixing units to ensure mixing efficiency.…”

Section: Resultsmentioning

confidence: 99%

“…Special geometries, such as serpentine [11], twisted [12], Tesla [13], etc. [14,15], can also generate chaotic fluid. However, the design process relies extensively on experience, which results in uncertain mixing performance.…”

Section: Introductionmentioning

confidence: 99%

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Chaotic Micromixer Based on 3D Horseshoe Transformation

Zhang

Chuai

et al. 2019

Micromachines

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To improve the efficiency of mixing under laminar flow with a low Reynolds number (Re), a novel three-dimensional Horseshoe Transformation (3D HT) was proposed as the basis for the design of a micromixer. Compared with the classical HT, the Lyapunov exponent of the 3D HT, which was calculated based on a symbolic dynamic system, proved the chaotic enhancement. Based on the 3D HT, a micromixer with a mixing length of 12 mm containing six mixing units was obtained by sequentially applying “squeeze”, “stretch”, “twice fold”, “inverse transformation”, and “intersection” operations. Numerical simulation and Peclet Number (Pe) calculations indicated that when the squeeze amplitude 0 < α < 1/2, 0 < β < 1/2, the stretch amplitude γ > 4, and Re ≥ 1, the mass transfer in the mixer was dominated by convective diffusion induced by chaotic flow. When Re = 10, at the outlet of the mixing chamber, the simulated mixing index was 96.4%, which was far less than the value at Re = 0.1 (σ = 0.041). Microscope images of the mixing chamber and the curve trend of pH buffer solutions obtained from a mixing experiment were both consistent with the results of the simulation. When Re = 10, the average mixing index of the pH buffer solutions was 91.75%, which proved the excellent mixing efficiency of the mixer based on the 3D HT.

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Section: Resultsmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 99%

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Chaotic Micromixer Based on 3D Horseshoe Transformation

Zhang

Chuai

et al. 2019

Micromachines

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“…A mixing index of 0.96 was obtained for Re=0.2. In a recent paper, Hossain et al [18] characterized the mixing performance of Newtonian fluids in two-layer crossing channels micromixer for Reynolds number ranging from 0.2 to 40. Their results outline that the mixing index reached 0.90 with variations of the geometric parameters even at creeping flow, Re = 0.2.…”

Section: Introductionmentioning

confidence: 99%

High mixing performances of shear-thinning fluids in two-layer crossing channels micromixer at very low Reynolds numbers

Amar

Lasbet

Makhlouf

2019

JMES

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In a recent study, the Two-Layer Crossing Channels Micromixer (TLCCM) exhibited good mixing capacities in the case of the Newtonian fluids (close to 100%) for all considered Reynolds number values. However, since the majority of the used fluids in the industrial sectors are non-Newtonians, this work details the mixing evolution of power-law fluids in the considered geometry. In this paper, the power-law index ranges from 0.73 to 1 and the generalized Reynolds number is bounded between 0.1 and 50. The conservation equations of momentum, mass and species transport are numerically solved using a CFD code, considering the species transport model. The flow structure at the cross-sectional planes of our micromixer was studied using the dynamic systems theory. The evolutions of the intensity, also the axial, radial and tangential velocity profiles were examined for different values of the Reynolds number and the power-law index. Besides, the pressure drop of the power-law fluids under different Reynolds number was calculated and represented. Furthermore, the mixing efficiency is evaluated by the computation of the mixing index (MI), based on the standard deviation of the mass fraction in different cross-sections. In such geometry, a perfect mixing is achieved with MI closed to 99.47 %, at very small Reynolds number (from the value 0.1) whatever the power-law index and generalized Reynolds numbers taken in this investigation. Consequently, the targeted channel presents a useful tool for pertinent mass transfer improvements, it is highly recommended to include it in various microfluidic systems. 5939 the case of creeping flows (Re of the order of 0.1). Temporary perturbation concerns twodimensional flows where solid boundaries and/or initial conditions are disturbed over time.Regarding the spatial perturbation, it makes the geometry twisted in the three directions of space. These perturbations break the flow regularity and so the chaotic flow is generated. For this subject, it became necessary to focus the efforts on the development of micromixers used in the different industrial domains such as bioengineering and chemical engineering, chemical synthesis, emulsion processes, polymerization [1], DNA analysis, two-phase flow separation [2], detection and analysis of chemical or biochemical content [3-4-5]. We can distinguish two main types of micromixers: active and passive micro-mixers [6]. Active micromixers use external energy sources to accentuate the flow agitation by, for example, a magnetic field, pressure field, and electrical field, etc. These types of micromixers are very efficient in terms of mixing [7] but they are more complex and expensive than passive micromixers. In addition, they required more detailed in terms of fabrication. Besides, passive micromixers are of great importance due to their simple structures and easy manufacturing [8]. Thus, the secondary flows resulting from the chaotic advection are very intense and many vortices of different sizes are generated. The large vortices improve the macroscopi...

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“…Active mixers require an external input, e.g., acoustics, electricity, or magnetic fields implying complex off‐chip setups. Passive mixers cause mixing by structural features inside the microfluidic channel that stretch and fold the liquids to induce shorter path lengths for diffusion . One particular example is the slanted groove mixer, consisting of a microchannel with a grooved wall.…”

Section: Introductionmentioning

confidence: 99%

Photoresponsive Passive Micromixers Based on Spiropyran Size‐Tunable Hydrogels

Schiphorst

Melpignano

Amirabadi

et al. 2017

Macromol. Rapid Commun.

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Microfluidic devices allow the manipulation of fluids down to the micrometer scale and are receiving a lot of attention for applications where low volumes and high throughputs are required. In these micro channels, laminar flow usually dominates, which requires long residence times of the fluids, limiting the flow speed and throughput. Here a switchable passive mixer has been developed to control mixing and to easily clean microchannels. The mixer is based on a photoresponsive spiropyran based hydrogel of which the dimensions can be tuned by changing the intensity of the light. The size-tunable gels have been used to fabricate a passive slanted groove mixer that can be switched off by light allowing to change mixing of microfluidics to non-mixed flows. These findings open new possibilities for multi-purpose microfluidic devices where mixers and valves can be tuned by light.

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

Cited by 13 publications

References 37 publications

Chaotic Micromixer Based on 3D Horseshoe Transformation

Chaotic Micromixer Based on 3D Horseshoe Transformation

High mixing performances of shear-thinning fluids in two-layer crossing channels micromixer at very low Reynolds numbers

Photoresponsive Passive Micromixers Based on Spiropyran Size‐Tunable Hydrogels

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