Finite Element Modeling of Suspended Particle Migration in Non-Newtonian Fluids

摘要

Shear-induced migration of particles is studied during the slow flow of suspensions of spheres (particle volume fraction theta=0.50) in an inelastic but shear-thinning, suspending fluid in flow between counterrotating concentric cylinders. The conditions are such that nonhydrodynamic effects are negligible. The movement of particles away from the high shear rate region is more pronounced than in a Newtonian suspending liquid. The authors test a continuum constitutive model for the evolution of particle concentration in a flowing suspension proposed by Philips et al. (1992) by using shear-thinning, suspending fluids. The fluid constitutive equation is Carreu-like in its shear-thinning behavior but also varies with the local particle concentration. The model is compared with the experimental data gathered with nuclear magnetic resonance (NMR) imaging.