Date of Award
Master of Science
Chemical and Paper Engineering
Dr. James E. Kline
Dr. Raymond Janes
Masters Thesis-Open Access
Under strong hydrodynamic forces, solids dispersions could no longer be considered isotropic fluid s but rather two-phase systems. The continuous (dispersing) phase was only sheared in side an effective gap determined in a Couette flow device by the presence of solid (dispersed) phase in to suspension. Three parameters, the effective gap, percent gap reduction and the relative shear volume, were incorporated to account for the influence of solids in the rheology of their suspension.
The objectives of this study were: (1) to investigate the role of solids volumetric concentration, particle size, nominal gap and continuous phase viscosity on Hercules Hi-Shear viscometric measurements of polystyrene spheres, and (2) to identify the occurrence of Taylor's vortical flow in stability in rheogram's flow curves. The obtained rheograms were evaluated in accordance of this kind of hydrodynamic instability and the latter was correlated with the observed break point in the increasing shear rate flow curves. Increased volume concentration of solids decreases the effective gap for shearing the continuous phase, increased the gap reduction, decreased the relative shear volume and, consequently, increased the measured viscosity. Finally, regression analysis was used to develop a semiempirical equation which correlated the ratio of the continuous phase viscosity to the measured apparent viscosity with solids volumetric concentration.
Triantafillopoulos, Nicholas G., "Shear Induced Anisotropy in the Rheology of Solids Dispersions" (1985). Masters Theses. 1470.