Pinch-off of bubbles in a polymer solution

Fuente: arXiv
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Autori principali: Rajesh, Sreeram, Peddada, Sumukh S, Thiévenaz, Virgile, Sauret, Alban
Natura: Preprint
Pubblicazione: 2022
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author Rajesh, Sreeram
Peddada, Sumukh S
Thiévenaz, Virgile
Sauret, Alban
author_facet Rajesh, Sreeram
Peddada, Sumukh S
Thiévenaz, Virgile
Sauret, Alban
contents The formation of gas bubbles in a liquid occurs in various engineering processes, such as during foam generation or agitation and mixing in bubbly flows. A challenge in describing the initial formation of a gas bubble is due to the singular behavior at pinch-off. Past experiments in Newtonian fluids have shown that the minimum neck radius follows a power-law evolution shortly before the break-up. The exponent of the power-law depends on the viscosity of the surrounding Newtonian liquid, and ranges from 0.5 for low viscosity to 1 for large viscosity. However, bubble formation in a viscoelastic polymer solution remains unclear, and in particular, if the evolution is still captured by a power-law and how the exponent varies with the polymer concentration. In this study, we use high-speed imaging to analyze the bubble pinch-off in solutions of polymers. We characterize the time evolution of the neck radius when varying the concentration and thus the characteristic relaxation time and describe the influence of viscoelasticity on the bubble pinch-off. Our results reveal that the presence of polymers does not influence the thinning until the latter stages, when their presence in sufficient concentration delays the pinch-off.
format Preprint
id arxiv_https___arxiv_org_abs_2209_06190
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Pinch-off of bubbles in a polymer solution
Rajesh, Sreeram
Peddada, Sumukh S
Thiévenaz, Virgile
Sauret, Alban
Soft Condensed Matter
The formation of gas bubbles in a liquid occurs in various engineering processes, such as during foam generation or agitation and mixing in bubbly flows. A challenge in describing the initial formation of a gas bubble is due to the singular behavior at pinch-off. Past experiments in Newtonian fluids have shown that the minimum neck radius follows a power-law evolution shortly before the break-up. The exponent of the power-law depends on the viscosity of the surrounding Newtonian liquid, and ranges from 0.5 for low viscosity to 1 for large viscosity. However, bubble formation in a viscoelastic polymer solution remains unclear, and in particular, if the evolution is still captured by a power-law and how the exponent varies with the polymer concentration. In this study, we use high-speed imaging to analyze the bubble pinch-off in solutions of polymers. We characterize the time evolution of the neck radius when varying the concentration and thus the characteristic relaxation time and describe the influence of viscoelasticity on the bubble pinch-off. Our results reveal that the presence of polymers does not influence the thinning until the latter stages, when their presence in sufficient concentration delays the pinch-off.
title Pinch-off of bubbles in a polymer solution
topic Soft Condensed Matter
url https://arxiv.org/abs/2209.06190