Displacement of Fluid Droplets From Solid Surfaces
Dimitrakopoulos, Panagiotis
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/82458
Description
Title
Displacement of Fluid Droplets From Solid Surfaces
Author(s)
Dimitrakopoulos, Panagiotis
Issue Date
1998
Doctoral Committee Chair(s)
Higdon, Jonathan J.L.
Department of Study
Chemical Engineering
Discipline
Chemical Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Engineering, Mechanical
Language
eng
Abstract
The displacement of fluid droplets from solid substrates is a fundamental problem of fluid mechanics. This problem has application in coating operations, enhanced oil recovery and vapor condensation. Our goal is to predict the yield conditions (capillary number Ca) as a function of physical parameters including viscosity ratio lambda, Bond number B d and advancing and receding contact angles thetaA and thetaR. To determine the yield conditions, we conduct a computational study employing a spectral implementation of the boundary integral method for Stokes flow. In these computations, we develop a novel Newton iteration algorithm which allows us to determine equilibrium interfaces in low Re flows. In earlier studies, the treatment of the contact line has been simplified by assuming fixed geometrical shapes such as circles or ellipses. In our study, we model the true physics by solving for the actual contour of the contact line as determined by the contact angle hysteresis thetaA -- thetaR. This model requires the solution of a nonlinear optimization problem: search over all possible contact line profiles to determine the configuration which minimizes the contact angle hysteresis for a given flow rate or gravitational force. Results are presented for the yield conditions for four model problems: drop displacement from plane solid substrates in low Re shear flows, gravitational displacement of droplets from inclined planes and the displacement of droplets and fluid bridges in pressure-driven flows. The study covers a wide range of all the parameters which affect the three problems. A number of significant results concerning the fundamental physics are revealed.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
