- Title
- Remarks on approaches that relate foam drainage rate to bubble terminal velocity
- Creator
- Li, Xueliang; Evans, Geoffrey M.; Stevenson, Paul
- Relation
- International Journal of Multiphase Flow Vol. 42, p. 24-28
- Publisher Link
- http://dx.doi.org/10.1016/j.ijmultiphaseflow.2011.12.009
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2012
- Description
- Approaches that relate to foam drainage rate and bubble terminal velocity are found to be problematic. This is mainly due to the inter-bubble normal force in the foam. Reported successful applications in the literature are due to faulty algorithms or visual illusions. We believe that various problems exist with these findings. By force balance analysis and observations of the sudden deceleration of the bubbles upon arrival at the foam-liquid interface, it is inferred that an inter-bubble normal force exists, and this is the main driving force for the foam to rise, however dry the foam is. The force balance analysis indicates that, if the inter-bubble normal force in a foam is neglected, the drag coefficient will be underestimated. This is supported by recently published experimental results.
- Subject
- drift-flux; slip velocity; bubbly liquid; foam; inter-bubble force; power-law
- Identifier
- http://hdl.handle.net/1959.13/1318998
- Identifier
- uon:23754
- Identifier
- ISSN:0301-9322
- Language
- eng
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