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Effects of surface viscosities on the stability of a draining plane parallel liquid film as a small bubble approaches a liquid‐gas interface
Author(s) -
Hahn P.S.,
Slattery J. C.
Publication year - 1985
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690310611
Subject(s) - surface tension , bubble , coalescence (physics) , van der waals force , viscosity , thermodynamics , instability , surface force , radius , chemistry , materials science , mechanics , physics , organic chemistry , molecule , computer security , astrobiology , computer science
When a small bubble is driven through a liquid phase to a liquid‐gas interface, a thin liquid film forms between them and drains until an instability forms and coalescence occurs. Following Lin and Slattery (1982b), Chen et al. (1984) and Hahn et al. (1985) analyzed this process, neglecting the effects of electrostatic forces and of the surface viscosities. Here we extend their theory to include the effects of the surface viscosities. We employ a modification of the development by Barber and Hartland (1976; Flumerfelt et al., 1982) for a draining film bounded by parallel planes. For a large intermediate range of the surface viscosities, the coalescence time is a strong function of these parameters. Inclusion of the surface viscosities acts to moderate or even reverse trends previously established for the dependence of the coalescence time on the bubble radius, the viscosity of the film liquid, the interfacial tension, the strength of the London‐van der Waals forces, and the density difference between the two phases.