Macroscopic behavior of bidisperse suspensions of noncolloidal particles in yield stress fluids

Vu, Thai-Son; Ovarlez, Guillaume; Château, Xavier

doi:10.1122/1.3439731

Cited by 42 publications

(32 citation statements)

References 28 publications

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“…Recent work has addressed the question of estimating the bulk yield stress of a yield stress suspension, according to the fraction of the dispersed phase. Theoretical developments in Chateau, Ovarlez & Trung (2008) agree reasonably well with the experimental results of Ovarlez, Bertrand & Rodts (2006) and Mahaut et al (2008), see also Ovarlez et al (2006), Coussot et al (2009), Vu, Ovarlez & Chateau (2010 and Ovarlez et al (2012). Of course, in dealing with suspensions the dispersed phase length scale is much smaller than that of the bulk flow, unlike here where the droplets are of the flow dimension and we focus on a continuous stream.…”

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confidence: 63%

Macro-size drop encapsulation

et al. 2015

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Viscoplastic fluids do not flow unless they are sufficiently stressed. This property can be exploited in order to produce novel flow features. One example of such flows is viscoplastically lubricated (VPL) flow, in which a viscoplastic fluid is used to stabilize the interface in a multi-layer flow, far beyond what might be expected for a typical viscous-viscous interface. Here we extend this idea by considering the encapsulation of droplets within a viscoplastic fluid, for the purpose of transportation, e.g. in pipelines. The main advantage of this method, compared to others that involve capillary forces is that significantly larger droplets may be stably encapsulated, governed by the length scale of the flow and yield stress of the encapsulating fluid. We explore this set-up both analytically and computationally. We show that sufficiently small droplets are held in the unyielded plug of a Poiseuille flow (pipe or plane channel). As the length or radius of the droplets increases, the carrier fluid eventually yields, potentially breaking the encapsulation. We study this process of breaking and give estimates for the limiting size of droplets that can be encapsulated.

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confidence: 63%

Macro-size drop encapsulation

et al. 2015

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“…Bournonville et al (2004) have slightly modified the model given by de Larrard (1999) to calculate the maximum volume fraction of bidisperse spherical systems. The modified model has been used in research work by Vu et al (2010). In this model, two different configurations of the bidisperse system are recognized: dominant small particle configurations (large particles are embedded in a small particle matrix) and dominant large particle configurations (small particles were inserted in the empty space between the large particles).…”

Section: Relative Viscosity Of Bimodal Suspensionsmentioning

confidence: 99%

Relative viscosity of bimodal suspensions

Tanner

2011

Korea-Aust. Rheol. J.

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A new differential (or multi-scale, mean field approach) model for the relative viscosity of bimodal suspensions is discussed in this paper. Solid spherical particles with a bimodal size distribution in a Newtonian solvent are considered. The problem of random close packing for a bidisperse system is studied. The bounds on volume fractions are given by , where the random close packing volume fraction for a monodisperse system, , is assumed. We propose that the bimodal suspension has a dominant large particle composition and that the small particles fill the empty spaces between the large particles. The model can therefore be based on the theory of monodisperse suspensions. The predictions of the relative viscosity for several bimodal suspensions given by the model are compared to experimental measurements. A reasonably good agreement is observed.

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“…The effect of particle size distribution on the structure of granular materials has been a subject of great interest [3,4,[33][34][35][36][37][38][39][40]. However, most investigations have mainly dealt with packing fraction.…”

Section: Introductionmentioning

confidence: 99%

Effect of size polydispersity versus particle shape in dense granular media

et al. 2014

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We present a detailed analysis of the morphology of granular systems composed of frictionless pentagonal particles by varying systematically both the size span and particle shape irregularity, which represent two polydispersity parameters of the system. The microstructure is characterized in terms of various statistical descriptors such as global and local packing fractions, radial distribution functions, coordination number, and fraction of floating particles. We find that the packing fraction increases with the two parameters of polydispersity, but the effect of shape polydispersity for all the investigated structural properties is significant only at low size polydispersity where the positional and/or orientational ordering of the particles prevail. We focus in more detail on the class of side/side contacts, which is the interesting feature of our system as compared to a packing of disks. We show that the proportion of such contacts has weak dependence on the polydispersity parameters. The side- side contacts do not percolate but they define clusters of increasing size as a function of size polydispersity and decreasing size as a function of shape polydispersity. The clusters have anisotropic shapes but with a decreasing aspect ratio as polydispersity increases. This feature is argued to be a consequence of strong force chains (forces above the mean), which are mainly captured by side-side contacts. Finally, the force transmission is intrinsically multiscale, with a mean force increasing linearly with particle size.

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Macroscopic behavior of bidisperse suspensions of noncolloidal particles in yield stress fluids

Cited by 42 publications

References 28 publications

Macro-size drop encapsulation

Macro-size drop encapsulation

Relative viscosity of bimodal suspensions

Effect of size polydispersity versus particle shape in dense granular media

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