@misc{10481/97934,
year = {2022},
month = {6},
url = {https://hdl.handle.net/10481/97934},
abstract = {We investigate experimentally the coalescence cascade process for a confined swarm
of deformable bubbles immersed in a bidimensional vertical cell filled with water. For
different gas volume fractions, air bubbles of size D0 larger than the cell thickness are
injected at the bottom of the cell. The bubbles swarms transformation is explored using
high-speed visualizations. The time evolution of each bubble in the swarm is determined
using a specifically developed algorithm, enabling bubble tracking and coalescence
detection. We determine the evolution of the bubble size distribution downstream from
the injection point, and show that the stages of the coalescence cascade are characterized
by the diameter, DV90, representative of the largest bubbles. The collision frequency of
pairs of bubbles of sizes Dk and Dk  , h(Dk,Dk  ), and their coalescence efficiency, λ, are
obtained from the experiments. The efficiency is nearly constant, independently of the
bubble sizes and of the gas volume fraction. Concerning collision frequency, our results
reveal the existence of two different coalescence regimes depending on the capability of
the bubbles to deform. Models describing h(Dk,Dk  ) for both regimes are provided. They
take into account the specific response of the bubble pair, which depends on the reduced
diameter Dp = 2DkDk /(Dk + Dk  ), to the global swarm-induced agitation governed by
DV90 and the gas volume fraction. In the first regime, occurring for smaller Dp, bubbles
are brought together by agitation and rapidly coalesce, while for sufficiently large Dp, both
bubbles are able to deform and spend more time adapting mutually their shapes before
coalescing.},
organization = {SpanishMINECO and European Funds under projects
DPI2017-88201-C3-2-R},
organization = {Programa Operativo FEDER Andalucía 2014–2020},
organization = {Consejería de
Economía y Conocimiento de la Junta de Andalucía under project 1263528},
organization = {French Agence Nationale de la Recherche (ANR) under reference ANR-19-CE43-0002-02
(ALLIGATOR project)},
organization = {Spanish MINECO for the financial support provided
by the fellowship BES-2015-071329},
organization = {Red Nacional para el Desarrollo de la Microfluídica,
RED2018-102829-T},
publisher = {Cambridge University Press},
keywords = {breakup/coalescence},
keywords = {gas/liquid flow},
keywords = {bubble dynamics},
title = {Coalescence of bubbles in a high Reynolds number confined swarm},
doi = {10.1017/jfm.2022.492},
author = {Ruiz Rus, J. and Ern, P. and Roig, V. and Martínez Bazán, Jesús Carlos},
}