TY - JOUR
T1 - Growth of a bubble cloud in CO2-saturated water under microgravity
AU - Vega-Martínez, Patricia
AU - Rodríguez-Rodríguez, Javier
AU - van der Meer, Devaraj
PY - 2020/5/28
Y1 - 2020/5/28
N2 - The diffusion-driven growth of a dense cloud of bubbles immersed in a gas-supersaturated liquid is a problem that finds applications in several modern technologies such as solvent-exchange micro-reactors, nanotechnology or the manufacturing of foamy materials. However, under Earth's gravity conditions, these dynamics can only be observed for a very limited time if the cloud is not attached to a surface, due to the action of buoyancy,i.e.of gravity effects. Here, we present experimental observations of the time evolution of dense bubble clouds growing in CO2-supersaturated water under microgravity conditions. We report the existence of three regimes where the bubble cloud exhibits different growth rates. At short times, each bubble grows independently following the Epstein-Plesset equation. Later on, bubbles start to interact with each other and their growth rate diminishes as they compete for the available CO2. When this happens, the growth rate slows down. This occurs earlier the deeper the bubble is in the cloud. Finally, at long times, only those bubbles on the husk continue growing. These regimes may be qualitatively described by a mathematical model where each individual bubble grows in the presence of a constellation of point mass sinks. Despite the model being only valid for dilute bubble clouds, its predictions are consistent with the experimental observations, even though the bubble clouds we observe are rather dense.
AB - The diffusion-driven growth of a dense cloud of bubbles immersed in a gas-supersaturated liquid is a problem that finds applications in several modern technologies such as solvent-exchange micro-reactors, nanotechnology or the manufacturing of foamy materials. However, under Earth's gravity conditions, these dynamics can only be observed for a very limited time if the cloud is not attached to a surface, due to the action of buoyancy,i.e.of gravity effects. Here, we present experimental observations of the time evolution of dense bubble clouds growing in CO2-supersaturated water under microgravity conditions. We report the existence of three regimes where the bubble cloud exhibits different growth rates. At short times, each bubble grows independently following the Epstein-Plesset equation. Later on, bubbles start to interact with each other and their growth rate diminishes as they compete for the available CO2. When this happens, the growth rate slows down. This occurs earlier the deeper the bubble is in the cloud. Finally, at long times, only those bubbles on the husk continue growing. These regimes may be qualitatively described by a mathematical model where each individual bubble grows in the presence of a constellation of point mass sinks. Despite the model being only valid for dilute bubble clouds, its predictions are consistent with the experimental observations, even though the bubble clouds we observe are rather dense.
KW - 22/2 OA procedure
UR - http://www.scopus.com/inward/record.url?scp=85083465703&partnerID=8YFLogxK
U2 - 10.1039/d0sm00015a
DO - 10.1039/d0sm00015a
M3 - Article
C2 - 32292997
AN - SCOPUS:85083465703
VL - 16
SP - 4728
EP - 4738
JO - Soft matter
JF - Soft matter
SN - 1744-683X
IS - 20
ER -