Numerical Simulations of the Flow of a Dense Suspension Exhibiting Yield-Stress and Shear-Thinning Effects

Abstract

Many types of dense suspensions are complex materials exhibiting both solid-like and fluid-like behavior. These suspensions are usually considered to behave as non-Newtonian fluids and the rheological characteristics such as yield stress, thixotropy and shear-thinning/thickening can have significant impact on the flow and the engineering applications of these materials. Therefore, it is important to understand the rheological features of these fluids. In this paper, we study the flow of a nonlinear fluid which exhibits yield stress and shear-thinning effects. The geometries of interests are a straight channel, a channel with a crevice and a pipe with a contraction; we assume the fluid behaves as a Herschel-Bulkley fluid. The numerical simulations indicate that for flows with low Reynolds number and high Bingham number an unyielded plug may form in the center of the channel. In the case of a channel with a crevice, the fluid in the deep portion of the crevice is at an extremely high level of viscosity, forming a plug which is hard to yield. For the pipe with a contraction, near the pipe neck the unyielded region is smaller due to the enhanced flow disturbance.

On the Response of a Herschel–Bulkley Fluid Due to a Moving Plate

“…Constitutive modeling of complex fluids [1], sometimes referred to as non-linear fluids or non-Newtonian fluids, has received much attention in the literature [2][3][4]. Most of the naturally occurring and synthetic fluids are non-linear fluids, for example, polymer melts, suspensions, blood, slurries, drilling fluids, mud, etc., [5][6][7]. There are many empirical or semi-empirical constitutive equations that have been suggested for these fluids.…”

Mathematical Modeling of Fluid Flow and Heat Transfer in Petroleum Industries and Geothermal Applications 2020

“…Many suspensions, composed of fluid and solid particles, behave as non-Newtonian fluids with rheological characteristics such as yield stress, thixotropy, and shear-thinning/thickening, etc. Li et al [12] look at the flow of a non-linear fluid with yield stress exhibiting shear-thinning effects in the following geometries: (i) a straight channel, (ii) a channel with a crevice, and (iii) a pipe with a contraction. They assume that the suspension behaves as a Herschel-Bulkley fluid.…”