Bubbling in a co-flow at high Reynolds numbers

The physical mechanisms underlying bubble formation from a needle in a co-flowing liquid environment at high Reynolds numbers are studied in detail with the aid of experiments and boundary-integral numerical simulations. To determine the effect of gas inertia the experiments were carried out with ai...

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Autores: Gordillo Arias de Saavedra, José Manuel, Sevilla, A., Martínez Bazán, C.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2007
País:España
Institución:Universidad de Sevilla (US)
Repositorio:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/57370
Acceso en línea:http://hdl.handle.net/11441/57370
https://doi.org/10.1063/1.2747996
Access Level:acceso abierto
Palabra clave:Bubbling
Reynolds numbers
Co-flow
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spelling Bubbling in a co-flow at high Reynolds numbersGordillo Arias de Saavedra, José ManuelSevilla, A.Martínez Bazán, C.BubblingReynolds numbersCo-flowThe physical mechanisms underlying bubble formation from a needle in a co-flowing liquid environment at high Reynolds numbers are studied in detail with the aid of experiments and boundary-integral numerical simulations. To determine the effect of gas inertia the experiments were carried out with air and helium. The influence of the injection system is elucidated by performing experiments using two different facilities, one where the constancy of the gas flow-rate entering the bubble is ensured, and another one where the gas is injected through a needle directly connected to a pressurized chamber. In the case of constant flow-rate injection conditions, the bubbling frequency has been shown to hardly depend on the gas density, with a bubble size given by db / ro  ? 6U? K * U + k2 /? U- 1? 1/3 for U? 2, where U is the gas-to-liquid ratio of the mean velocities, ro is the radius of the gas injection needle, and k * = 5,84 and k2 = 4,29, whit db / ro3,3U1 / 3 for U1.. Nevertheless, in this case the effect of gas density is relevant to describe the final instants of bubble breakup, which take place at a time scale much smaller than the bubbling time, tb. This effect is evidenced by the liquid jets penetrating the gas bubbles upon their pinch-off. Our measurements indicate that the velocity of the penetrating jets is considerably larger in air bubbles than in helium bubbles due to the distinct gas inertia of both situations. However, in the case of constant pressure supply conditions, the bubble size strongly depends on the density of the gas through the pressure loss along the gas injection needle. Furthermore, under the operating conditions reported here, the equivalent diameters of the bubbles are between 10% and 20% larger than their constant flow-rate counterparts. In addition, the experiments and the numerical results show that, under constant pressure supply, helium bubbles are approximately 10% larger than air bubbles due to the gas density effect on the bubbling process.AIP PublishingIngeniería Aeroespacial y Mecánica de FluidosTEP103: Mecánica de Fluidos2007info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfapplication/pdfhttp://hdl.handle.net/11441/57370https://doi.org/10.1063/1.2747996reponame:idUS. Depósito de Investigación de la Universidad de Sevillainstname:Universidad de Sevilla (US)InglésPhysics of fluids, 19 (7), 077102-1-077102-18.http://aip.scitation.org/doi/abs/10.1063/1.2747996info:eu-repo/semantics/openAccessoai:idus.us.es:11441/573702026-06-17T12:51:07Z
dc.title.none.fl_str_mv Bubbling in a co-flow at high Reynolds numbers
title Bubbling in a co-flow at high Reynolds numbers
spellingShingle Bubbling in a co-flow at high Reynolds numbers
Gordillo Arias de Saavedra, José Manuel
Bubbling
Reynolds numbers
Co-flow
title_short Bubbling in a co-flow at high Reynolds numbers
title_full Bubbling in a co-flow at high Reynolds numbers
title_fullStr Bubbling in a co-flow at high Reynolds numbers
title_full_unstemmed Bubbling in a co-flow at high Reynolds numbers
title_sort Bubbling in a co-flow at high Reynolds numbers
dc.creator.none.fl_str_mv Gordillo Arias de Saavedra, José Manuel
Sevilla, A.
Martínez Bazán, C.
author Gordillo Arias de Saavedra, José Manuel
author_facet Gordillo Arias de Saavedra, José Manuel
Sevilla, A.
Martínez Bazán, C.
author_role author
author2 Sevilla, A.
Martínez Bazán, C.
author2_role author
author
dc.contributor.none.fl_str_mv Ingeniería Aeroespacial y Mecánica de Fluidos
TEP103: Mecánica de Fluidos
dc.subject.none.fl_str_mv Bubbling
Reynolds numbers
Co-flow
topic Bubbling
Reynolds numbers
Co-flow
description The physical mechanisms underlying bubble formation from a needle in a co-flowing liquid environment at high Reynolds numbers are studied in detail with the aid of experiments and boundary-integral numerical simulations. To determine the effect of gas inertia the experiments were carried out with air and helium. The influence of the injection system is elucidated by performing experiments using two different facilities, one where the constancy of the gas flow-rate entering the bubble is ensured, and another one where the gas is injected through a needle directly connected to a pressurized chamber. In the case of constant flow-rate injection conditions, the bubbling frequency has been shown to hardly depend on the gas density, with a bubble size given by db / ro  ? 6U? K * U + k2 /? U- 1? 1/3 for U? 2, where U is the gas-to-liquid ratio of the mean velocities, ro is the radius of the gas injection needle, and k * = 5,84 and k2 = 4,29, whit db / ro3,3U1 / 3 for U1.. Nevertheless, in this case the effect of gas density is relevant to describe the final instants of bubble breakup, which take place at a time scale much smaller than the bubbling time, tb. This effect is evidenced by the liquid jets penetrating the gas bubbles upon their pinch-off. Our measurements indicate that the velocity of the penetrating jets is considerably larger in air bubbles than in helium bubbles due to the distinct gas inertia of both situations. However, in the case of constant pressure supply conditions, the bubble size strongly depends on the density of the gas through the pressure loss along the gas injection needle. Furthermore, under the operating conditions reported here, the equivalent diameters of the bubbles are between 10% and 20% larger than their constant flow-rate counterparts. In addition, the experiments and the numerical results show that, under constant pressure supply, helium bubbles are approximately 10% larger than air bubbles due to the gas density effect on the bubbling process.
publishDate 2007
dc.date.none.fl_str_mv 2007
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11441/57370
https://doi.org/10.1063/1.2747996
url http://hdl.handle.net/11441/57370
https://doi.org/10.1063/1.2747996
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Physics of fluids, 19 (7), 077102-1-077102-18.
http://aip.scitation.org/doi/abs/10.1063/1.2747996
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv AIP Publishing
publisher.none.fl_str_mv AIP Publishing
dc.source.none.fl_str_mv reponame:idUS. Depósito de Investigación de la Universidad de Sevilla
instname:Universidad de Sevilla (US)
instname_str Universidad de Sevilla (US)
reponame_str idUS. Depósito de Investigación de la Universidad de Sevilla
collection idUS. Depósito de Investigación de la Universidad de Sevilla
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.301629

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