Repository logo
 

Experimental and simulation studies of the shape and motion of an air bubble contained in a highly viscous liquid flowing through an orifice constriction

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Hallmark, B 
Chen, C-H 
Davidson, JF 

Abstract

This paper reports an experimental and computational study on the shape and motion of an air bubble, contained in a highly viscous Newtonian liquid, as it passes through a rectangular channel having a constriction orifice. The magnitude of the viscosity ratios, λ, and capillary numbers, CA, explored is high: 5.5 x 105 < λ < 3.9 x 106 and 2.9 < Ca < 35.9 respectively. A multipass rheometer is used for the experimental work: air bubbles are suspended in 10 Pa s and 70 Pa s polybutene viscosity standards and passed through an orifice-plate geometry constructed within an optical flow-cell. High levels of bubble distortion are observed, including bubbles that resemble ‘crescent moons’. Simulation work is carried out using an implementation of the volume of fluid method in the freely-available finite-volume computational fluid dynamics code OpenFOAM. Quantitative data pertaining to the motion and shape of the bubble was extracted from both the experimental and simulation work. Initially, a good match between numerical simulation and experimental work could not be obtained: this problem was alleviated by changing the viscosity averaging method from an arithmetic mean to a logarithmically-weighted arithmetic mean. Medium- and high-resolution simulations using this new viscosity averaging method were able to match experimental data with coefficients of determination, R2, typically 0.898 < R2 < 0.985.

Description

Keywords

Multipass rheometer, Two-phase flow, Bubble motion, Volume of fluid method, OpenFOAM, Viscosity averaging rules

Journal Title

Chemical Engineering Science

Conference Name

Journal ISSN

0009-2509
1873-4405

Volume Title

Publisher

Elsevier BV
Sponsorship
Engineering and Physical Sciences Research Council (EP/N00230X/1)
Funding is gratefully acknowledged from the EPSRC, grant EP/N00230X/1.