Shear‐induced migration and axial development of particles in channel flows of non‐Brownian suspensions

Abstract

We present an experimental study on the shear-induced migration and axial development of particles in the channel flows of non-Brownian suspensions. The suspending fluid is Newtonian. We investigate fracturing flows with a Hele-Shaw type scaling through building a unique channel setup and an advanced optical system. The local particle concentration profiles are measured via the refractive-index matching technique for a wide range of bulk volume fraction, that is, 0:1 ≤ ϕ b ≤ 0:5. Simultaneously, the particle image velocimetry is performed to determine the velocity profile of the particle phase. We compare our experimental results with the available two-phase continuum frameworks and show discrepancies and similarities in the fully developed and axial development of the solid volume fraction profiles. We discuss directions in which the continuum frameworks require improvements.

Solvents govern rheology and jamming of polymeric bead suspensions

“…Despite these slight variations, we find the main result already highlighted by Chatté et al 4 and then by Lobry et al 15 : the decrease of the friction coefficient as a function of the normal force is a key point that accounts quantitatively for shear thinning in frictional suspensions. The black lines are the fit curves using Equations ( 10) & (11) with X a = 1.85, α 0 = 1, α ∞ = 0.65, X p = 2.3, ϕ ∞ J = 0.555, and ϕ 0 J = 0.63. These values are very close to those obtained by Arshad et al 5 (see table 1).…”

“…1 Examples for these suspensions include paints, cement pastes, cosmetics, cocoa paste, cornstarch-water mixtures. Despite their few constituents, concentrated suspensions of hard non-Brownian particles in a Newtonian fluid display very complex flow behaviors: 2 shear thinning, [3][4][5] shear thickening, [6][7][8] density inhomogeneities, [9][10][11] etc. The understanding of these behaviors -simple at first glance -has remained limited until a major advance made by Boyer et al 12 .…”

Interface-resolved simulations of the confinement effect on the sedimentation of a sphere in yield-stress fluids

“…Moreover, it has been observed through experimental measurements and fully-resolved particle simulations that the confining walls substantially affect the dynamics of the suspension flows in the Newtonian fluids through the structuring of the suspension into layers in the vicinity of the confining walls. [20,21,22,23].…”

Instability in suspensions oscillating along narrow channels

“…As the volume fraction ϕ increases, the profiles become increasingly blunted in the center. This a consequence of the shear-induced migration of particles from regions of high velocity gradient near the walls (y/H = ±0.5) to regions of low one near the center (y/H = 0), know to occur in pressure-driven flows [13], [14]. This migration produces a higher concentration of particles in the center than near the walls, which results in a nonuniform viscosity across the gap and the blunted velocity profiles.…”