Fluid imbibition in paper fibers: precursor front
Eduardo N de Azevedo1, Lars R Alme, M Engelsberg
1Programa de Pós-Graduação em Ciência de Materiais, Universidade Federal de Pernambuco, Cidade Universitária, 50.670-901, Recife, Pernambuco, Brazil.
Summary
Nuclear magnetic resonance imaging reveals non-Fickian water transport in paper. Effective diffusivity varies with pore saturation, showing a faster precursor front in partially filled pores.
Area of Science:
- Materials Science
- Fluid Dynamics
- Physics
Background:
- Understanding fluid transport in porous media is crucial for applications like papermaking and filtration.
- Paper's complex pore structure influences fluid imbibition dynamics.
Purpose of the Study:
- To investigate water penetration and transport diffusivity in paper under varying conditions.
- To analyze the non-Fickian nature of fluid transport in porous materials.
Main Methods:
- Utilized nuclear magnetic resonance (NMR) imaging to observe water imbibition in paper samples.
- Measured kinetics of imbibition profiles to determine transport properties.
- Analyzed data considering non-Fickian transport models.
Main Results:
- Determined the dependence of effective transport diffusivity on the degree of pore saturation.
- Observed non-Fickian transport behavior in the paper samples.
- Identified a precursor fluid front with significantly higher diffusivity than in saturated pores.
Conclusions:
- The study elucidates the complex, non-Fickian water transport mechanisms in paper.
- Effective transport diffusivity is a key parameter reflecting saturation-dependent fluid movement.
- The precursor front phenomenon highlights distinct transport behaviors in partially versus fully saturated pores.
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