Film Drainage between Colliding Drops at Constant Approach Velocity: Experiments and Modeling.

Experiments and modeling of the drainage of the thin liquid film between two deformable spherical drops approaching each other at constant velocity in another liquid are being presented. Two numerical models based on the lubrication theory have been developed considering the cases of immobile or mobile drop interfaces. The absolute film thickness and the thinning rate have been measured using laser interferometry for a wide range of capillary numbers. In all studied cases, the model with immobile interfaces was found to give the best predictions of the experimental time evolution of the film thickness and radial expansion. These results made it possible to derive a typical time scale of the drainage process. Copyright 2000 Academic Press.

[1]  J. C. Slattery,et al.  Effects of London‐van der Waals forces on the thinning of a dimpled liquid film as a small drop or bubble approaches a horizontal solid plane , 1982 .

[2]  S. Jeelani,et al.  Effect of Interfacial Mobility on Thin Film Drainage , 1994 .

[3]  A. Sheludko,et al.  Thin liquid films , 1967 .

[4]  D. R. Woods,et al.  Change in interface and film shapes for a deformable drop at a deformable liquid-liquid interface , 1969 .

[5]  I. Ivanov,et al.  Hydrodynamics of thin liquid films. Effect of surfactants on the velocity of thinning of emulsion films , 1977 .

[6]  S. G. Yiantsios,et al.  On the buoyancy-driven motion of a drop towards a rigid surface or a deformable interface , 1990, Journal of Fluid Mechanics.

[7]  D. R. Woods,et al.  Film shapes for deformable drops at liquid-liquid interfaces. II. The mechanisms of film drainage , 1973 .

[8]  J. C. Lee,et al.  Film flow and coalescence-I Basic relations, film shape and criteria for interface mobility , 1968 .

[9]  S. G. Mason,et al.  The coalescence of liquid drops with flat liquid/liquid interfaces , 1960 .

[10]  Hydrodynamics of thin liquid films. Rate of thinning of emulsion films from pure liquids , 1976 .

[11]  Ak Allen Chesters,et al.  The drainage and rupture of partially-mobile films between colliding drops at constant approach velocity , 1994 .

[12]  J. C. Slattery,et al.  Thinning of a liquid film as a small drop or bubble approaches a solid plane , 1982 .

[13]  S. G. Mason,et al.  The approach of gas bubbles to a gas/liquid interface , 1961 .

[14]  S. G. Mason,et al.  The gravity approach and coalescence of fluid drops at liquid interfaces , 1963 .

[15]  J. C. Slattery,et al.  Thinning of a liquid film as a small drop or bubble approaches a fluid–fluid interface , 1982 .

[16]  S. Jeelani,et al.  Dimple formation in the thin film beneath a drop or bubble approaching a plane surface , 1994 .