Library Subscription: Guest
Home Archives Officers Future meetings American Society of Thermal and Fluids Engineering
First Thermal and Fluids Engineering Summer Conference

ISSN: 2379-1748
ISBN: 978-1-56700-430-4

NUMERICAL AND EXPERIMENTAL INVESTIGATION OF BUBBLE ATTACHMENT TO A SUBSTRATE

DOI: 10.1615/TFESC1.mph.012563
pages 1929-1938

Javad Esmaeelpanah
Center for Advanced Coating Technologies, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada, M5S 3G8

Pavani Cherukupally
Center for Advanced Coating Technologies (CACT), Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada, M5S 3G8

Sanjeev Chandra
Center for Advanced Coating Technologies, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada, M5S 3G8

Javad Mostaghimi
Center for Advanced Coating Technologies, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada, M5S 3G8


KEY WORDS: bubble impact, simulation, volume-of-fluid, roughness

Abstract

A combined numerical and experimental study was performed to study the attachment of bubbles to solid surfaces immersed in water. A 1.3 mm diameter air bubble was injected from a needle into a column of water. The horizontal test substrate was submerged underwater above the tip of the needle. The distance from the tip of the needle to the substrate was varied from 1 to 10 mm to study the effect of impact velocity and bubble deformation prior to impact on bubble attachment. Glass (hydrophilic) and Teflon (hydrophobic) surfaces were tested. It was observed that at higher impact velocities (0.24 m/s, near the bubble terminal velocity) the bubble bounced off the substrate several times before finally attaching to the surface. At low impact velocity (~0.1 m/s) bubbles attach to the surface without bouncing. Bubbles attached readily to hydrophobic surfaces on which the liquid film separating the bubble and substrate ruptured more easily. The multiphase fluid flow equations were solved with a numerical scheme that uses a two-step projection technique. The interfacial surface tension force was modeled as a body force using a continuum-surface-force (CSF) technique. A volume-of-fluid method and Youngs algorithm were employed to track and reconstruct the free surface. Bubble motion and impact were simulated and liquid pressures and velocities that prevent attachment to the surface calculated. The results shows that a film does not rupture at higher impact speed due to lower interaction time. Additionally, it was found that the roughness stabilizes the ruptured film.

Purchase $20.00 Check subscription Publication Ethics and Malpractice Recommend to my Librarian Bookmark this Page