Cavitation bubble dynamics and sonochemiluminescence activity inside sonicated submerged flow tubes

Busra Ekim Sarac; Dwayne Savio Stephens; Julian Eisener; Juan Manuel Rosselló; Robert Mettin

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arXiv · 2011.14797

Cavitation bubble dynamics and sonochemiluminescence activity inside sonicated submerged flow tubes

Busra Ekim Sarac·Dwayne Savio Stephens·Julian Eisener·Juan Manuel Rosselló·Robert Mettin

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Abstract

Bubble dynamics and luminol emissions of cavitation in sub-millimeter-sized PFA flow tubes, submerged in an ultrasonic bath reactor, are studied at 27 kHz driving frequency. Nucleation of cavitation inside the tubes only takes place via a free interface, realized here in form of an alternating water-air slug flow. High-speed recordings show that cavitation bubbles in the water slugs often develop localized structures in form of clusters or bubble plugs, and that such structures can be seeded via a single pinch-off from the free interface. Within the structures, bubbles strongly interact and frequently undergo merging or splitting events. Due to the mutual interaction and resulting motion, bubbles often collapse with a fast displacement, suggesting jetting dynamics. Bubble compression ratios are estimated on basis of observed individual bubble dynamics and numerical fitting by a single bubble model. The resulting peak temperatures around 3000 K allow for dissociation of water vapor. This is in accordance with observed sonochemiluminescence from luminol, originating from active bubble zones in the tubes.

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Busra Ekim Sarac, Dwayne Savio Stephens, Julian Eisener, Juan Manuel Rosselló, Robert Mettin. 2020-10-06. Cavitation bubble dynamics and sonochemiluminescence activity inside sonicated submerged flow tubes. https://arxiv.org/abs/2011.14797

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