CAREER: Suspensions of Noncolloidal Particles in Yield Stress Fluids: Fluid Mechanics, Rheology and Microstructure

点击翻译按钮获取中文摘要

CBET - 1554044PI: Hormozi, SarahSlurries are concentrated suspensions of particles in a viscous liquid. They are found in natural settings, such as landslides, mudslides, and underwater avalanches, and in industrial settings, such as in tailings from mining operations. The goal of this CAREER project is to develop experimental and modeling methods to examine the fluid dynamical behavior of slurries when the viscous liquid that conveys the particles exhibits complex behavior on its own. The experiments will cover a wide range of flow regimes, and the results will fill an important knowledge gap in understanding the flow characteristics of slurries. This understanding is essential to make accurate predictions of how natural disasters start and spread and to avoid or reduce their impacts. Data acquired in the project will be useful to researchers who are interested in developing new models of slurries and to practitioners who develop equipment to process these complex materials. In addition, results from the project will be incorporated into classes at Ohio University. Researchers working on the project will participate in a variety of outreach programs, including TechSavvy, a career conference for girls and the adults who support them, and a residential Technology Camp for high school girls that provides opportunities for young women to explore careers in engineering and technology.This CAREER project focuses on the development of experimental and modeling techniques to investigate rheological properties of slurries in which the suspending liquid by itself exhibits non-Newtonian behavior, including a yield stress and shear-thinning. For example, this is the case in mine tailings and debris, where small colloidal particles impart non-Newtonian behavior to the suspending liquid that affects the rheology of suspensions of larger, noncolloidal particles. The experiments will span low-Reynolds number to inertial regimes, and will determine the particle pressure tensor and the kinetics of shear-induced migration of the particles. Radiography and three-dimensional micro-tomography will be used to determine the local volume fraction of the particles and the local stress components. Particle imaging and tracking velocimetry will be used to characterize the underlying microstructure, i.e., the spatial and temporal arrangement of the particles, and connect it to the macroscopic rheology of the slurry. Results will be used to develop accurate theoretical frameworks to model geophysical flows and predict initiation, spreading dynamics and runout, which will help limit the impact of natural disasters.