Pore-scale visualization of the mobilization of a partially wetting droplet

Shao Yiu Hsu, Markus Hilpert

Research output: Contribution to journalArticle

Abstract

We experimentally investigated the mobilization process of a partially wetting droplet in a pore doublet model. The process, involving contact line movement, liquid film generation, and interface deformation, has not been fully understood and modeled. In equilibrium, the droplet sat in one of the capillary tubes of the pore doublet, and the contact lines of the droplet were pinned with nonzero contact angles. The droplet was subject to pressure differences that were generated by pumping the continuous liquid into the pore doublet at different flow rates. At low flow rates, the droplet moved with sliding contact lines, and the shapes of the droplet's menisci roughly resembled spherical caps. When the flow rate increased, the velocity of the droplet increased, and the shapes of the liquid-liquid interfaces changed dramatically forming finger-like structures and films. Once films form, the classical Young-Laplace equation, which assumes a spherical interface, is not sufficient to describe droplet mobilization and the corresponding pressure drops. The films ruptured as the droplet moved forward, and a certain amount of droplet liquid was left behind. When the flow rates reached a certain level, the droplet snapped off from the tube wall and rolled while being surrounded by thin films formed by the continuous liquid.

Original languageEnglish (US)
JournalAdvances in Water Resources
DOIs
StateAccepted/In press - Jan 30 2015

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wetting
droplet
visualization
mobilization
liquid
pressure drop
low flow
sliding
pumping
rate

Keywords

  • Droplet mobilization
  • Partial wetting
  • Pore-scale experiment
  • Visualization

ASJC Scopus subject areas

  • Water Science and Technology

Cite this

Pore-scale visualization of the mobilization of a partially wetting droplet. / Hsu, Shao Yiu; Hilpert, Markus.

In: Advances in Water Resources, 30.01.2015.

Research output: Contribution to journalArticle

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