Liquid velocity field measurements during bubble formation and detachment at an orifice

Vidinha, T. and Dempster, W.M. and Stickland, M.T. (2001) Liquid velocity field measurements during bubble formation and detachment at an orifice. In: 9th International Conference on Laser Anemometry, 2001-09-12 - 2001-09-14.

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Abstract

This paper discusses the formation of gas bubbles at orifices with the purpose of experimentally investigating the influence of the surrounding liquid velocity field. The liquid velocity field measurements are established using PIV techniques utilising an Argon-ion laser to illuminate the fluorescent seeding. The images are recorded using high-speed digital video and the PIV results are obtained by cross correlation of the acquired images. Optical filters are used in an attempt to remove the glare from the bubble interface. The liquid velocity field was determined for the single bubble regime over a range of gas flowrates and orifice diameters of 2 mm and 6 mm. The investigation revealed a number of phenomena that are important to the growth of the bubble. These include liquid re-circulation due to necking, the extent of the influence of the preceding bubble and appearance of vortex rings generated by interface oscillations.