Relationship between particle focusing and dimensionless numbers in elasto-inertial focusing

2016 ◽  
Vol 55 (11-12) ◽  
pp. 889-900 ◽  
Author(s):  
Hyeong Yong Song ◽  
Seung Hak Lee ◽  
Reza Salehiyan ◽  
Kyu Hyun
Lab on a Chip ◽  
2021 ◽  
Author(s):  
Shohei Kishimoto ◽  
Makusu Tsutsui ◽  
Kazumichi Yokota ◽  
Masateru Taniguchi

Electrokinetics in octet nanochannels was demonstrated to enable particle focusing via inertial effects to accurate single-nanoparticle zeta-potential measurements.


2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Joo Young Kwon ◽  
Dong-Ki Lee ◽  
Jungwoo Kim ◽  
Young Hak Cho

AbstractIn this study, particle focusing phenomena are studied in parallelogram and rectangular cross-sectioned microchannels of varying aspect ratio. In contrast to prior work the microchannels were fabricated using anisotropic wet etching of a Si wafer, plasma bonding, and self-alignment between the Si channel and the PDMS mold. It is shown that the inertial focusing points of the fabricated microchannels of parallelogram and rectangular cross-section were modified as the aspect ratio of the microchannels changed. The particle focusing points of the parallelogram profiled microchannel are compared with those of the rectangular microchannel through experimental measurements and CFD simulation. It is shown that particles can be efficiently focused and separated at a relatively low Reynolds number using a parallelogram profiled microchannel with a low aspect ratio.


Soft Matter ◽  
2020 ◽  
Vol 16 (12) ◽  
pp. 3096-3105
Author(s):  
Pengju Yin ◽  
Lei Zhao ◽  
Zezhou Chen ◽  
Zhiqiang Jiao ◽  
Hongyan Shi ◽  
...  

Inertial microfluidic chips were fabricated using commercial 3D-printers and the particle focusing was implemented in channels.


2022 ◽  
Vol 32 (2) ◽  
pp. 025007
Author(s):  
Shuang Chen ◽  
Zongqian Shi ◽  
Jiajia Sun ◽  
Shenli Jia ◽  
Mingjie Zhong ◽  
...  

Abstract Inertial microfluidic has been widely applied to manipulate particles or bio-sample based on the inertial lift force and Dean Vortices. This technology provides significant advantages over conventional technologies, including simple structure, high throughput and freedom from an external field. Among many inertial microfluidic systems, the straight microchannel is commonly used to produce inertial focusing, which is a phenomenon that particles or cells are aligned and separated based on their size under the influence of inertial lift force. Besides the inertial lift force, flow drag forces induced by the geometrical structures of microchannel can also affect particle focusing. Herein, a split-recombination microchannel, consisting of curved and straight channels, is proposed to focus and separate particles at high flow rate. As compared with the straight channel, the particle focusing in the split-recombination channel is greatly improved, which results from the combined effects of the inertial lift force, the curvature-induced Dean drag force and the structure of split and recombination. Moreover, the distribution of different-sized particles in designed microchannel is investigated. The results indicate that the proposed microchannel not only enhances the particle focusing but also enables the separation of different-sized particles with high throughput. Finally, it is discovered that the larger length of straight channel and curvature radius of curved channel can result in a more efficient particle separation. Another important feature of designed split-recombination microchannel is that it can be arranged in parallel to handle large-volume samples, holding great potential in lab-on-a-chip applications.


Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1242
Author(s):  
Hiroshi Yamashita ◽  
Takeshi Akinaga ◽  
Masako Sugihara-Seki

The continuous separation and filtration of particles immersed in fluid flows are important interests in various applications. Although the inertial focusing of particles suspended in a duct flow is promising in microfluidics, predicting the focusing positions depending on the parameters, such as the shape of the duct cross-section and the Reynolds number (Re) has not been achieved owing to the diversity of the inertial-focusing phenomena. In this study, we aimed to elucidate the variation of the inertial focusing depending on Re in rectangular duct flows. We performed a numerical simulation of the lift force exerted on a spherical particle flowing in a rectangular duct and determined the lift-force map within the duct cross-section over a wide range of Re. We estimated the particle trajectories based on the lift map and Stokes drag, and identified the particle-focusing points appeared in the cross-section. For an aspect ratio of the duct cross-section of 2, we found that the blockage ratio changes transition structure of particle focusing. For blockage ratios smaller than 0.3, particles focus near the centres of the long sides of the cross-section at low Re and near the centres of both the long and short sides at relatively higher Re. This transition is expressed as a subcritical pitchfork bifurcation. For blockage ratio larger than 0.3, another focusing pattern appears between these two focusing regimes, where particles are focused on the centres of the long sides and at intermediate positions near the corners. Thus, there are three regimes; the transition between adjacent regimes at lower Re is found to be expressed as a saddle-node bifurcation and the other transition as a supercritical pitchfork bifurcation.


Author(s):  
Alireza Setayesh Hagh ◽  
Ali Dinler

Inertial focusing has attracted a significant attention in microfluidics applications in recent years. Inertial focusing occurs only under specific flow conditions at which particles migrate across streamlines to a specific number of equilibrium positions. This behavior is mostly not sensitive to the particle size in straight channels. However, curved channels can allow sized based particle separation. In this study, curved channels with various aspect ratios have been investigated by numerical simulations. Consideration of flow regimes reveals that some conditions establish a high-quality single-particle focusing situation which is characterized by the alignment of particles within a narrow band. The outcomes of our numerical model contribute to the understanding of limitation of particle focusing and particle separation in curved microchannels.


Author(s):  
Caio Araujo ◽  
Tiago Ferreira Souza ◽  
Maurício Figueiredo ◽  
valdir estevam ◽  
Ana Maria Frattini Fileti

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 412
Author(s):  
Kaan Erdem ◽  
Vahid Ebrahimpour Ahmadi ◽  
Ali Kosar ◽  
Lütfullah Kuddusi

Label-free, size-dependent cell-sorting applications based on inertial focusing phenomena have attracted much interest during the last decade. The separation capability heavily depends on the precision of microparticle focusing. In this study, five-loop spiral microchannels with a height of 90 µm and a width of 500 µm are introduced. Unlike their original spiral counterparts, these channels have elliptic configurations of varying initial aspect ratios, namely major axis to minor axis ratios of 3:2, 11:9, 9:11, and 2:3. Accordingly, the curvature of these configurations increases in a curvilinear manner through the channel. The effects of the alternating curvature and channel Reynolds number on the focusing of fluorescent microparticles with sizes of 10 and 20 µm in the prepared suspensions were investigated. At volumetric flow rates between 0.5 and 3.5 mL/min (allowing separation), each channel was tested to collect samples at the designated outlets. Then, these samples were analyzed by counting the particles. These curved channels were capable of separating 20 and 10 µm particles with total yields up to approximately 95% and 90%, respectively. The results exhibited that the level of enrichment and the focusing behavior of the proposed configurations are promising compared to the existing microfluidic channel configurations.


Meccanica ◽  
2021 ◽  
Author(s):  
I. Banerjee ◽  
M. E. Rosti ◽  
T. Kumar ◽  
L. Brandt ◽  
A. Russom

AbstractWe report a unique tuneable analogue trend in particle focusing in the laminar and weak viscoelastic regime of elasto-inertial flows. We observe experimentally that particles in circular cross-section microchannels can be tuned to any focusing bandwidths that lie between the “Segre-Silberberg annulus” and the centre of a circular microcapillary. We use direct numerical simulations to investigate this phenomenon and to understand how minute amounts of elasticity affect the focussing of particles at increasing flow rates. An Immersed Boundary Method is used to account for the presence of the particles and a FENE-P model is used to simulate the presence of polymers in a Non-Newtonian fluid. The numerical simulations study the dynamics and stability of finite size particles and are further used to analyse the particle behaviour at Reynolds numbers higher than what is allowed by the experimental setup. In particular, we are able to report the entire migration trajectories of the particles as they reach their final focussing positions and extend our predictions to other geometries such as the square cross section. We believe complex effects originate due to a combination of inertia and elasticity in the weakly viscoelastic regime, where neither inertia nor elasticity are able to mask each other’s effect completely, leading to a number of intermediate focusing positions. The present study provides a fundamental new understanding of particle focusing in weakly elastic and strongly inertial flows, whose findings can be exploited for potentially multiple microfluidics-based biological sorting applications.


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