Spontaneous Imbibition of Liquid in Glass fiber Wicks, Part II: Validation of a Diffuse‐front Model

What is it about?

In Part I of this two series paper, we propose a model based on sharp liquid-front. Although it showed a good agreement with some cases with sharp liquid front, it failed to account for partial saturation in some wicks. Hence, we tried to solve Richard's equation to predict liquid saturation numerically in 2D using COMSOL and analytically in 1D using Mathematica for glass-fiber wicks as transversely-isotropic porous media. In order to validate the numerical and theoretical results, the saturation along the wick length is determined experimentally through a new liquid-N2 based freezing technique and a good agreement between the numerical/analytical predictions and experimental results are achieved in saturation distributions.

Featured Image

Why is it important?

In some applications, the wicking phenomenon happens under partial saturation condition and instead of an absolute sharp liquid front, we are confronted with a diffusive front in which Darcy's law is unable to predict it in term of the actual height of the front as a function of time. Our investigation provides a novel solution to these kinds of phenomenon.