An experimental investigation has been undertaken on the growth and departure of bubbles from artificial nucleation sites. Bubbles were produced by gas diffusion from a carbonated water solution on 0.6, 1.48 and 2.08 mm diameter cavities in a horizontal plate. The departure size and growth time of the bubbles produced in the experiments could not be accurately predicted using a force balance analysis and the assumed initial growth condition of a bubble nucleus. A numerical simulation was developed to solve these parameters. This showed that the bubble grows very rapidly after a neck forms. Experiments in which the bubbles grew to a height which was several times the cavity diameter revealed that departure occurred during the rapid growth. The numerical simulation also predicted accurately the volume of the residual bubble inside the cavity and the time until the succeeding bubble appeared above the cavity opening. The effect of surface tension on the bubble departure diameter was found to aid departure by the formation of a bubble neck rather than resisting departure as an adherent force that attached the bubble to the surface.
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