Numerical simulation of the effects of non-Newtonian property of the solvent on particle suspension rheology

Abstract

To investigate the effects of the non-Newtonian properties of solvents on particle suspension rheology (non-Newtonian property and viscosity), we analyzed suspension flows with different solvent characteristics. We used the power-law model to express the non-Newtonian properties of solvents. The power-law index of the suspension was denoted as nsus. and that of the solvent as [Formula: see text] to distinguish between their non-Newtonian properties. Besides, to evaluate the non-Newtonian property of the particle suspension, we estimated its power-law index [Formula: see text] by comparing its particle velocity with the velocity profile of a power-law fluid. As a result, regardless of the different area fraction, the power-law index of the particle suspension was lower than that of the solvent for [Formula: see text], 0.8, and 1.0. On the other hand, for [Formula: see text] and [Formula: see text], the power-law index of the particle suspension was higher than that of the solvent. Regarding the particle position, particles for [Formula: see text] were more concentrated on the wall side than those of the suspensions with [Formula: see text], 0.8, and 1.0. Thus, this study confirms that a change in the non-Newtonian property of a suspension due to interactions between particles and power-law fluids is an essential factor when discussing the rheology of suspensions.

Numerical Analysis of Non-Newtonian Fluid Effects on the Equilibrium Position of a Suspended Particle and Relative Viscosity in Two-Dimensional Flow

“…In this study, in order to consider particle inertial effects, Reynolds number Re was set to 32, i.e., the particle Reynolds number Re p = 0.32. These are the same conditions as that of the previous study [12]. We used a circular rigid particle with a diameter of 2r as a suspended particle in this study.…”

“…Concerning studies about rheology using non-Newtonian fluid, Tanaka et al [11] suggested that non-Newtonian properties of a solvent affected the relative viscosity and intrinsic viscosity of suspensions. Masuyama and Fukui [12] reported that a power-law fluid affects particle migration and rheological property in an inertial flow. As mentioned above, many studies have used a Newtonian fluid as a solvent, and power-law fluid has often been used in the studies about non-Newtonian fluid.…”