Free Surface Modeling Using CFD: Bubble Bursting

Bubble bursting is a process where bubble rises up to a surface of a liquid and
experiences bubble film breaks and liquid jet. Invisible to the naked eyes, these two
events produce droplets known as film drops and jet drops. There are a lot of industrial
problems that are pertinent to these droplets and these problems are very important to be
properly handled as they can affect the working environment and workers’ health.
Realizing the importance of bubble bursting phenomenon, this project has the objective
to capture the bubble bursting mechanisms by using CFD and to study the effect of
surface tension and initial bubble diameter on bubble bursting mechanism. CFD package
that is used in this study is FLUENT 12.0 and the tracking method used is Volume-of-
Fluid (VOF). The cases are run for two different surface tension which are 1.2 N/m and
1.4 N/m and two different initial bubble diameter which are 11.5 mm and 9.3 mm. In
terms of bubble bursting, the main events of this phenomenon have been captured
successfully by CFD where the disintegration of bubble cap and production of liquid jet
are observed. However in terms of film and jet droplets formation, this simulation does
not show any formation of droplets from the bubble bursting causing no conclusion can
be made to relate direct relation between surface tension and initial bubble diameter to
the formation of droplets. Improvement can be made to have finer mesh to capture
possible formation of droplets in the system