Diffusion-driven growth of a dense bubble cloud in supersaturated liquids under microgravity conditions (DWS)

abstract

The purpose of this research is to investigate the growth of a bubble cloud produced upon the collapse of a cavitation bubble in carbonated liquids with high concentration of surfactants. Previous investigations report that the diameter of the cloud, L, initially grows as L ∼ t1/2, consistently with the behavior expected for an isolated bubble immersed in a supersaturated solution. This growth regime lasts only for about 10 ms since, after some time, the growth of the bubble cloud slows down, presumably due to the depletion of CO2 around and inside the cloud. Unfortunately, the investigation of this second regime -although highly relevant from an industrial and fundamental perspective- is difficult, as buoyancy (i.e. gravity), quickly takes over thus transforming the nearly spherical foam cloud into a plume.

Thus, we propose to repeat the experiments reported in Rodríguez-Rodríguez et. al (2014) in reduced gravity conditions, with the aim at determining the scaling of the size of the foam ball beyond the limit imposed by the onset of the buoyancy-driven flow. Because of the short duration of the experiment and the need to avoid large accelerations before conducting the experiment, we propose to use the tower in the drop mode. A better understanding of the formation of foam in reduced gravity conditions is highly relevant for many manufacturing processes, including those occurring in microgravity, as well as to understand a variety of geological phenomena.

• Vega-Martínez P,  Rodríguez-Rodríguez J, van der Meer D. and Sperl M. Drop tower setup to study the diffusion-driven growth of a foam ball in supersaturated liquids in microgravity condition. Microgravity science and Technology. doi:10.1007/s12217-017-9547-8 (2017)
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• Rodríguez-Rodríguez J, Casado-Chacón A and Fuster D. Physics of beer tapping. Phys. Rev. Lett. 113, 214501 (2014)
• Epstein PS and Plesset MS. Stability of gas bubbles in liquid-gas solutions. J. Chem. Phys. 18, 1505-1509 (1950)
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experiment year: 2016
number of drops: 10