Date of Award
12-2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Mechanical Engineering
Committee Chair/Advisor
Joshua Bostwick
Committee Member
John Saylor
Committee Member
Xiangchun Xuan
Abstract
Capillary rise in confined geometries plays a critical role in numerous natural and industrial processes. While classical models such as the Lucas–Washburn equation accurately describe the dynamics of Newtonian fluids, they fail to capture the complex behavior of shear-thinning, non- Newtonian fluids whose viscosity varies with shear rate. This research investigates the capillary rise dynamics of shear-thinning xanthan gum polymer solutions in capillary tubes. The rheological behavior of each fluid is characterized using the Ellis model, which accounts for shear-thinning effects through three key parameters: zero-shear viscosity μ0, characteristic shear stress τ1/2 and viscosity index α. Experimental data was collected for a range of xanthan gum polymer concentrations and the rise dynamics were rescaled using dimensionless parameters to evaluate deviations from classical scaling laws for Newtonian fluids to assess the role of shear-thinning effects. Results show that increasing shear-thinning behavior leads to reduced rise rates and a departure from the h ∝ t1/2 behavior expected for Newtonian fluids. We assess the universal rescaling framework proposed by Steinek et al. (2024), Physical Review Fluids, 8, 023305, based on the Ellis model, and explore its effectiveness and limitations in collapsing experimental data onto a unified master curve. These findings offer valuable insight into the interplay between fluid rheology and capillary dynamics, with implications for the design of systems involving non-Newtonian transport in porous media or narrow geometries.
Recommended Citation
Sayster, Aimee, "Capillary Imbibition of Shear-Thinning Xanthan Gum Solutions" (2025). All Theses. 4643.
https://open.clemson.edu/all_theses/4643