Rheology of concentrated suspensions and shear-induced migration
Mercredi 14 décembre 2011
à 14 h en salle C. Brot
This thesis deals with an experimental and numerical investigation of the phenomenon of shear-induced particle migration in inhomogeneous shear flows of mono-dispersed non-colloidal suspensions at neglected inertia. Variety of diffusion flux models that predict the shear-induced migration were presented. However, in this work, the Suspension Balance Model (SBM) is adopted. The latter describes the migration flux of particles as the divergence of the particle Stress tensor. According to the need for the different measurable parameters in this Model, a new experiment was developed for measuring the viscosity, the two Normal Stress Differences and the particle stress tensor of mono-dispersed non-Brownian suspensions of hard spheres flowing between rotating parallel disks over a wide range of concentrations (0.20 - 0.46). The original SBM is modified based on the new measurements. The Finite Volume Method via the OpenFOAM package is used as the technique to solve the problem numerically. Solutions are generated and results are compared to similar ones generated with the original model. Finally,the SBM model is extended into two-dimensional situations within a general Frame-Invariant structure that takes into account the local kinematics of the suspension.
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