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Sahaf, Seyed AmirHossein

University of British Columbia

The ability of paper towels in rapidly absorbing water is a critical feature, making them essential for cleaning, personal hygiene, and various household tasks. The porous structure of paper towels facilitates water absorption, a spontaneous process dominantly governed by capillary forces, viscous resistance, and gravitational forces. Since paper towels are primarily used for rapidly absorbing spills, it is crucial to study the initial rate of wicking and the factors that influence it. Understanding how the moisture content (MC) evolves within the paper towel during the wicking process is equally important. This research aims to investigate the parameters that govern these dynamics, including pore structure, gravitational effects, and inter-layer interactions in multi-ply configurations. To address this, a series of experiments is conducted using paper towels from four commercial brands: Bounty, Tuff, Sparkle, and Georgia-Pacific. Vertical and horizontal wicking rates and moisture content evolution are measured using optical and infrared imaging techniques. Single-ply and multi-ply configurations are studied to investigate the impact of layering on wicking behavior. Capillary rise length over time and moisture distribution are analyzed to identify distinct flow regimes and compare the performance of the samples. The results of vertical wicking, where gravity is present, reveal distinct wicking regimes, including an initial super-diffusive phase characterized by rapid water uptake, followed by a sub-diffusive phase in the later stages. In contrast, the late regime in horizontal wicking is diffusive. The initial phase is more pronounced in multi-ply configurations. Additionally, the MC evolves linearly with time initially, gradually asymptoting to its saturation level. The rate of this evolution varies among samples and between vertical and horizontal tests. Furthermore, while the highest MC saturation level remains constant along the length of the samples in horizontal wicking, it decreases with elevation in vertical wicking. Conceptual insights are provided to explain these phenomena, focusing on the effects of pore size heterogeneity.

Text

2024-12-20

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/89959

Mechanical Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/