On the pressure-driven flow of suspensions: Particle migration in apparent yield-stress fluids

Autor: P. R. de Souza Mendes, I.R. Siqueira
Rok vydání: 2019
Předmět:
Zdroj: Journal of Non-Newtonian Fluid Mechanics. 265:92-98
ISSN: 0377-0257
DOI: 10.1016/j.jnnfm.2019.02.002
Popis: Suspensions of particles with viscoplastic characteristics are often found both in nature and industrial applications. However, in contrast with the case of suspensions in Newtonian fluids, the dynamics of shear-induced particle migration in yield-stress suspending materials is not yet fully understood. In this work, we present a numerical study of particle migration in pressure-driven, tube flows of suspensions of non-colloidal, spherical particles dispersed in apparent yield-stress fluids. The suspension viscosity is modeled using the classical Krieger–Dougherty equation with a novel regularized viscosity function for viscoplastic materials as the suspending medium viscosity, and the dynamics of shear-induced particle migration is described with the Diffusive Flux Model. The resulting fully coupled, non-linear, one-dimensional model is solved with a second-order finite difference scheme coupled with Newton’s method. We present a parametric study that elucidates the role played by the suspension bulk concentration, Plastic number, and power-law index on the velocity profile and particle concentration distribution in the flow. Remarkably, the results show that particle migration in apparent yield-stress fluids leads to a strikingly different pattern of velocity and particle distribution profiles relative to the case of suspensions in Newtonian liquids and true yield-stress materials.
Databáze: OpenAIRE
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