Viscous fingering of a draining suspension

Yun Chen, Frank Malambri, Sungyon Lee

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The liquid drainage is a commonplace process that affects a wide array of industrial applications ranging from medical procedures and manufacturing processes to food processing. While many drainage-related applications involve the complex fluids comprising solid particles, the effects of suspended particles on the liquid drainage have not been considered, leaving simple fundamental questions on the suspension drainage unanswered. In this paper, we experimentally investigate the effects of particles on drainage by withdrawing suspensions from an air-filled Hele-Shaw cell in a radial sink flow. As expected, viscous fingering arises as air invades a draining viscous suspension. Despite numerous studies on viscous fingering, only a few have studied this "inward" viscous fingering for pure liquids and none for suspensions. We find that, while the overall behavior of fingering remains unchanged from the pure liquid case, suspended particles are shown to delay the onset of fingering but also to accelerate its growth rate. This surprising dual effect of particles results in the increase of the total drainage time and in the amount of drained suspension as a function of particle concentrations. In addition, the particle entrainment into the thin film of wetting oil causes particles with select sizes to remain on the channel walls instead of draining, which closely follows our simple theoretical prediction.

Original languageEnglish
Article number094002
JournalPhysical Review Fluids
Volume3
Issue number9
DOIs
StatePublished - Sep 24 2018

Bibliographical note

Funding Information:
The authors wish to thank Dr. Jungchul Kim for fruitful discussions and Dr. Irmgard Bischofberger (MIT) for her helpful feedback on the manuscript. The financial support for this work was provided by the Texas A&M Engineering Experiment Station (TEES). F.M. acknowledges an Undergraduate Summer Research Grant at Texas A and M University for funding.

Publisher Copyright:
© 2018 American Physical Society.

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