Particle migration in a Couette apparatus: Experiment and modeling

Tetlow, Nicholas; Graham, Alan L.; Ingber, M. S.; Subia, Samuel R.; Mondy, Lisa Ann; Altobelli, Stephen A.

doi:10.1122/1.550954

Cited by 108 publications

(73 citation statements)

References 15 publications

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“…Experimental results at very high particle concentration showed that particle migration could reduce the disperse phase concentration up to 10 times near a solid rotating wall for a Taylor-Couette system (Tetlow and Graham 1998). Such a decrease is consistent with the depletion calculated from the present CFD simulations (2 times lower), since in the current case there is a radial drag due to perfusion acting on the cells.…”

Section: Discussionsupporting

confidence: 90%

CFD simulation of an internal spin-filter: evidence of lateral migration and exchange flow through the mesh

et al. 2009

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In the present work Computational Fluid Dynamics (CFD) was used to study the flow field and particle dynamics in an internal spin-filter (SF) bioreactor system. Evidence of a radial exchange flow through the filter mesh was detected, with a magnitude up to 130-fold higher than the perfusion flow, thus significantly contributing to radial drag. The exchange flow magnitude was significantly influenced by the filter rotation rate, but not by the perfusion flow, within the ranges evaluated. Previous reports had only given indirect evidences of this exchange flow phenomenon in spin-filters, but the current simulations were able to quantify and explain it. Flow pattern inside the spinfilter bioreactor resembled a typical Taylor-Couette flow, with vortices being formed in the annular gap and eventually penetrating the internal volume of the filter, thus being the probable reason for the significant exchange flow observed. The simulations also showed that cells become depleted in the vicinity of the mesh due to lateral particle migration. Cell concentration near the filter was approximately 50% of the bulk concentration, explaining why cell separation achieved in SFs is not solely due to size exclusion. The results presented indicate the power of CFD techniques to study and better understand spin-filter systems, aiming at the establishment of effective design, operation and scale-up criteria.

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Section: Discussionsupporting

confidence: 90%

CFD simulation of an internal spin-filter: evidence of lateral migration and exchange flow through the mesh

et al. 2009

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“…Specifically, we consider an ambient Couette velocity field u θ = −r/3 + 1323/r and an ambient Poiseuille velocity field again given by u(z) = 1.083−0.75 * (z −0.66) 2 . The Couette velocity field is actually taken from previous physical experiments [4]. The angle that the line-of-centers of the particle pair and the ambient flow direction is 30 o in the case considered here.…”

Section: Resultsmentioning

confidence: 99%

“…However, the underlying physics has not been completely elucidated, resulting in less than satisfactory rheological models. In particular, current rheological models have been deficient in several regards including the scaling of particle migration rate with respect to characteristic particle size, incorporation of slip boundary conditions, and nonisotroic effects caused by particle agglomeration and chaining [3,4].…”

Section: Introductionmentioning

confidence: 99%

Particle interactions in oscillatory Stokes flow

Ingber¹,

Vorobieff²

2013

Computational Methods in Multiphase Flow VII

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It has been observed both experimentally and numerically for relatively dense suspension flows that small-amplitude oscillating Poiseuille flow results in particle migration towards the high shear rate region of the flow field (pipe walls), whereas, large-amplitude oscillating Poiseuille flow results in particle migration towards the low shear rate region of the flow field (pipe centerline). To date, there has been no satisfactory explanation as to why the period of oscillation has this effect on the direction of particle migration. In the current paper, we demonstrate through numerical simulation the same behavior in two-particle systems which provides a first principle explanation of at least one cause for this phenomenon in dense suspension flows. The numerical analysis is based on a semi-analytic solution for the motion of two spheres suspended in arbitrary, unbounded shear flow.

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“…This flow problem was the object of an experimental study by Abbott et al [27] and reinvestigated both numerically and experimentally by Tetlow et al [10]. The experimental apparatus has the inner rod (R i ) of 0.64 cm and the inner radius of the outer tube (R o ) of 2.38 cm (see Figure 2).…”

Section: Circular Couette Flowmentioning

confidence: 99%

“…Phillips et al [8] introduced the diffusive flux model based on the concept of particle concentration 453 diffusion. Experimental validation of the model for simple 1D or 2D problems is shown in References [9,10]. The suspension balance model was first introduced by Nott and Brady [11], who introduced the concept of suspension 'temperature'.…”

Section: Introductionmentioning

confidence: 99%

Three‐dimensional free surface flow simulation of segregating dense suspensions

Ilinca

Hétu

2008

Numerical Methods in Fluids

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SUMMARYThis paper presents a 3D numerical solution algorithm for the simulation of free surface flows of dense suspensions including particle migration phenomena. Segregation of the solid phase in processes such as powder injection molding and molding of semi-solid materials affects the rheology of the mixture and therefore the filling pattern. Segregation affects also the final properties and characteristics of such molded parts as a non-uniform particles distribution leads to non-uniform shrinkage, warpage and non-uniform mechanical properties. In this paper, particle migration is modeled using the diffusion flux model of Phillips et al. (Phys. Fluids A 1992; 4:30-40) and is extended to address 3D mold filling problems. The solution algorithm is validated against flow problems for which experimental and numerical data are available: circular Couette flow, piston-driven flow and sudden contraction-expansion flow. The particle migration model is then used to simulate mold filling problems in which the piston movement in the sleeve is known to induce particle migration before the material enters the cavity. An arbitrary Lagrangian-Eulerian (ALE) formulation is developed and combined to a level-set front capturing method to simulate the piston movement and the evolution of the free surface in molding simulations. The ALE formulation is first compared with an Eulerian solution for the case of the piston-driven flow problem. The approach is then applied to injection molding problems to study the evolution of particle distributions during molding and in the final molded parts.

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Particle migration in a Couette apparatus: Experiment and modeling

Cited by 108 publications

References 15 publications

CFD simulation of an internal spin-filter: evidence of lateral migration and exchange flow through the mesh

CFD simulation of an internal spin-filter: evidence of lateral migration and exchange flow through the mesh

Particle interactions in oscillatory Stokes flow

Three‐dimensional free surface flow simulation of segregating dense suspensions

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