Inertial migration of spherical and oblate particles in straight ducts

Lashgari, Iman; Ardekani, Mehdi Niazi; Banerjee, Indradumna; Russom, Aman; Brandt, Luca

doi:10.1017/jfm.2017.189

Cited by 74 publications

(65 citation statements)

References 42 publications

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“…They showed that by increasing the bulk Reynolds number to 120, the particle ring breaks and four particle focusing (equilibrium) points are observed at the duct wall centers. The same behavior for particle distributions across the duct cross section has also been observed experimentally by Abbas et al [21] Finally, in a recent paper Lashgari et al [24] performed numerical simulations to study the inertial migration of oblate particles in squared and rectangular ducts.…”

Section: Introductionsupporting

confidence: 68%

Inertial migration in dilute and semidilute suspensions of rigid particles in laminar square duct flow

et al. 2017

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We study the inertial migration of finite-size neutrally buoyant spherical particles in dilute and semi-dilute suspensions in laminar square duct flow. We perform several direct numerical simulations using an immersed boundary method to investigate the effects of the bulk Reynolds number Re b , particle Reynolds number Re p and duct to particle size ratio h/a at different solid volume fractions φ, from very dilute conditions to 20%. We show that the bulk Reynolds number Re b is the key parameter in inertial migration of particles in dilute suspensions. At low solid volume fraction (φ = 0.4%) and low bulk Reynolds number (Re b = 144), particles accumulate at the center of the duct walls. As Re b is increased, the focusing position moves progressively towards the corners of the duct. At higher volume fractions, φ = 5, 10 and 20%, and in wider ducts with Re b = 550, particles are found to migrate away from the duct core towards the walls. In particular, for φ = 5 and 10%, particles accumulate preferentially at the corners. At the highest volume fraction considered, φ = 20%, particles sample all the volume of the duct, with a lower concentration at the duct core.For all cases, we find that particles reside longer times at the corners than at the wall centers. In a duct with lower duct to particle size ratio h/a (i.e. with larger particles), Re b = 144 and φ = 5% we find that particles preferentially accumulate around the corners. Hence, the volume fraction plays a key role in defining the final distribution of particles in semi-dilute suspensions. The presence of particles induces secondary cross-stream motions in the duct cross-section, for all φ. The intensity of these secondary flows depends strongly on particle rotation rate, on the maximum concentration of particles in focusing positions, and on the solid volume fraction. We find that the secondary flow intensity increases with the volume fraction up to φ = 5%. However, beyond φ = 5% excluded volume effects lead to a strong reduction of cross-stream velocities. Inhibiting particles from rotating also results in a substantial reduction of the secondary flow intensity, and in variations of the exact location of the focusing positions.

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Section: Introductionsupporting

confidence: 68%

Inertial migration in dilute and semidilute suspensions of rigid particles in laminar square duct flow

et al. 2017

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“…In addition, the particles from different initial positions except the symmetric planes migrated to the same equilibrium position (approximately 0.2 H away from the channel wall). The qualitative migration processes and quantitative equilibrium position both agree well with the literature ( Lashgari et al, 2017 ). In the second case, we calculated the lateral lift force coefficient f L = F z /( ρ f U 3 f/ H ) for further quantitative comparison, which has been obtained by Di Carlo et al (2009) and Nakagawa et al (2015) with finite element method and immersed boundary method, respectively.…”

Section: Methodssupporting

confidence: 87%

“…To validate the accuracy of our in-house code based on the IB-LBM, two benchmark cases were implemented. The first one is the lateral migration of a freely moving and neutrally buoyant particle in a 3D square microchannel filled with liquid at Re c = 100, referred to the previous literature ( Lashgari, Ardekani, Banerjee, Russom, & Brandt, 2017 ). The geometry and the particle migration trajectories in the channel cross-section are shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

Inertial migration of aerosol particles in three-dimensional microfluidic channels

2021

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“…In square ducts the situation is more complex. Depending on the same parameters, the focusing positions can occur at the wall bisectors, along heteroclinic orbits or only at the duct corners (Chun & Ladd 2006;Abbas et al 2014;Nakagawa et al 2015;Kazerooni et al 2017;Lashgari et al 2017a).…”

Section: Introductionmentioning

confidence: 99%

Suspensions of finite-size neutrally buoyant spheres in turbulent duct flow

et al. 2018

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We study the turbulent square duct flow of dense suspensions of neutrally-buoyant spherical particles. Direct numerical simulations (DNS) are performed in the range of volume fractions φ = 0−0.2, using the immersed boundary method (IBM) to account for the dispersed phase. Based on the hydraulic diameter a Reynolds number of 5600 is considered. We report flow features and particle statistics specific to this geometry, and compare the results to the case of two-dimensional channel flows. In particular, we observe that for φ = 0.05 and 0.1, particles preferentially accumulate on the corner bisectors, close to the duct corners as also observed for laminar square duct flows of same duct-to-particle size ratios. At the highest volume fraction, particles preferentially accumulate in the core region. For channel flows, in the absence of lateral confinement particles are found instead to be uniformily distributed across the channel. We also observe that the intensity of the cross-stream secondary flows increases (with respect to the unladen case) with the volume fraction up to φ = 0.1, as a consequence of the high concentration of particles along the corner bisector. For φ = 0.2 the turbulence activity is strongly reduced and the intensity of the secondary flows reduces below that of the unladen case. The friction Reynolds number increases with φ in dilute conditions, as observed for channel flows. However, for φ = 0.2 the mean friction Reynolds number decreases below the value for φ = 0.1.

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Inertial migration of spherical and oblate particles in straight ducts

Cited by 74 publications

References 42 publications

Inertial migration in dilute and semidilute suspensions of rigid particles in laminar square duct flow

Inertial migration in dilute and semidilute suspensions of rigid particles in laminar square duct flow

Inertial migration of aerosol particles in three-dimensional microfluidic channels

Suspensions of finite-size neutrally buoyant spheres in turbulent duct flow

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