New Generalized Viscosity Model for Non-Colloidal Suspensions and Emulsions

Abstract

The viscous behavior of solids-in-liquid suspensions and liquid-in-liquid emulsions of non-Brownian solid particles and liquid droplets dispersed in Newtonian liquids is thoroughly discussed and reviewed. The full concentration range of the dispersed particles/droplets is covered, that is, 0<ϕ<ϕm, where ϕ is the volume fraction of inclusions (particles or droplets) and ϕm is the maximum packing volume fraction of inclusions. The existing viscosity models for suspensions and emulsions are evaluated using a large pool of experimental viscosity data on suspensions and emulsions. A new generalized model for the viscosity of suspensions and emulsions is proposed and evaluated. The model takes into consideration the influence of shear-induced aggregation of particles and droplets. It also includes the effect of the droplet-to-matrix viscosity ratio λ on the viscosity of emulsions. In the limit of high ratio of droplet viscosity to matrix viscosity (λ→∞), the model reduces to the suspension viscosity model. The proposed model uncovers some important and novel characteristics of suspension systems rarely discussed heretofore in the literature. The model is validated using twenty sets of experimental viscosity data on solids-in-liquid suspensions and twenty-three sets of experimental viscosity data on liquid-in-liquid emulsions.

Hydrothermal Treatment of Bitumen Froth: Impact of Mineral Solids and Water on Bitumen Properties

“…In the literature, various theoretical models are available to predict the viscosity of different mixtures such as suspensions, bitumen–organic solvent mixtures, and water-in-oil (W/O) emulsions. − Some of these models were used to correct the measured viscosity of the contaminated bitumen in this study. Their corresponding equations and assumptions based on which these equations are applicable can be found in Section S5 (Tables S4 and S5) of the Supporting Information.…”

Rheology of Emulsions Thickened by Starch Nanoparticles

“…The viscosity increases with the increase in nanoparticle concentration. The relative viscosity of nanoparticle suspensions can be described adequately by the following Pal viscosity model [ 38 ] for suspensions: where is the relative viscosity, is the volume fraction of particles, is the maximum packing volume fraction of particles, and is the intrinsic viscosity of suspension. The value of is taken as , corresponding to random packing of spheres.…”

“…The viscosity increases with the increase in nanoparticle concentration. The relative viscosity of nanoparticle suspensions can be described adequately by the following Pal viscosity model [38] for suspensions:…”

TES Nanoemulsions: A Review of Thermophysical Properties and Their Impact on System Design

“…Some equations that are used for estimating the viscosity of nanoemulsions were created for viscosity calculations for nanosuspensions and can only be used if one assumes liquid droplets' behavior to be the same as that of rigid solid particles (the viscosity ratio is defined as droplets' viscosity/continuous fluid viscosity, λ = µ d /µ c -i.e., λ → ∞ ). Some historically important proposed equations are included in Table 1; their premises, assumptions, and some of their limitations/drawbacks are discussed by Pal [113].…”