Capillary transport in paper porous materials at low saturation levels

TL;DR

This paper investigates capillary liquid transport in fibrous porous materials at low saturation, demonstrating a super-fast nonlinear diffusion process supported by microscopic simulations and qualitative experimental comparisons.

Contribution

It introduces a macroscopic super-fast nonlinear diffusion model for low saturation capillary transport in fibrous materials, validated by microscopic network simulations.

Findings

Liquid spreading follows a super-fast nonlinear diffusion model.

Microscopic network simulations support the macroscopic model.

Qualitative agreement with experimental observations was achieved.

Abstract

The problem of capillary transport in fibrous porous materials at low levels of liquid saturation has been addressed. It has been demonstrated, that the process of liquid spreading in this type of porous materials at low saturation can be described macroscopically by a similar super-fast, non-linear diffusion model as that, which had been previously identified in experiments and simulations in particulate porous media. The macroscopic diffusion model has been underpinned by simulations using a microscopic network model. The theoretical results have been qualitatively compared with available experimental observations using persistent liquids.