A Photographic Investigation of Bubble Nucleation from Artificial Cavities

Abstract

High speed motion pictures of bubble nucleation from glass capillaries were obtained. The fluids used were: distilled water, water with wetting agent, water with sucrose, and ethanol. Capillaries of cylindrical, conical, and reentrant geometries were used with inner diameters ranging from .0182 to .0381 inches. The penetration of the liquid-vapor interface into a cavity after bubble departure appeared to be inertia controlled. Cavity interior geometry and cleanliness had a direct effect upon the liquid-vapor interface penetration distance. The depth of penetration of the interface increased as cavity size increased. Viscosity reduced the interface penetration. Bubble growth curves were obtained for a typical bubble i n each fluid. Bubble departure diameter appeared to be independent of cavity geometrybut increased as cavity size increased. Viscosity retarded bubble growth during the initial stages of growth.