SELF-SIMILARITY OF VERTICAL BUBBLY JETS

SELF-SIMILARITY OF VERTICAL BUBBLY JETS

AbstractAn integral model for vertical bubbly jets with nearly monodisperse bubble sizes is presented. The model is based on the Gaussian type self-similarity of mean liquid velocity, bubble velocity and void fraction, as well as on functional relationships for initial liquid jet velocity and radius, bubble diameter and relative velocity. Adjusting the model to experimental data available in the literature for a wide range of densimetric Froude numbers provide constant values for the entrainment coefficient, momentum amplification factor, and spreading ratio of the bubble core for different flow conditions. Consistency and sensitivity of key model parameters are also verified. Overall, the deviations between model predictions and axial/radial profiles of mean liquid velocity, bubble velocity and void fraction are lower than about 20%, which suggests that bubbly jets tend to behave as self-preserving shear flows, similarly to single-phase jets and plumes. Furthermore, model simulations indicate a behavior similar to those of single-phase buoyant jets and slurry jets, but some differences with respect to confined bubbly jets are highlighted. This article provides not only a contribution to the problem of self-similarity in two-phase jets, but also a comprehensive model that can be used for analysis of artificial aeration/mixing systems involving bubbly jets.

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Main Author: Lima Neto,I. E.
Format: Digital revista
Language:English
Published: Brazilian Society of Chemical Engineering 2015
Online Access:http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0104-66322015000200475
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spelling oai:scielo:S0104-663220150002004752015-10-08SELF-SIMILARITY OF VERTICAL BUBBLY JETSLima Neto,I. E. Bubbles Gaussian profiles Integral model Jets Self-preservation AbstractAn integral model for vertical bubbly jets with nearly monodisperse bubble sizes is presented. The model is based on the Gaussian type self-similarity of mean liquid velocity, bubble velocity and void fraction, as well as on functional relationships for initial liquid jet velocity and radius, bubble diameter and relative velocity. Adjusting the model to experimental data available in the literature for a wide range of densimetric Froude numbers provide constant values for the entrainment coefficient, momentum amplification factor, and spreading ratio of the bubble core for different flow conditions. Consistency and sensitivity of key model parameters are also verified. Overall, the deviations between model predictions and axial/radial profiles of mean liquid velocity, bubble velocity and void fraction are lower than about 20%, which suggests that bubbly jets tend to behave as self-preserving shear flows, similarly to single-phase jets and plumes. Furthermore, model simulations indicate a behavior similar to those of single-phase buoyant jets and slurry jets, but some differences with respect to confined bubbly jets are highlighted. This article provides not only a contribution to the problem of self-similarity in two-phase jets, but also a comprehensive model that can be used for analysis of artificial aeration/mixing systems involving bubbly jets.info:eu-repo/semantics/openAccessBrazilian Society of Chemical EngineeringBrazilian Journal of Chemical Engineering v.32 n.2 20152015-06-01info:eu-repo/semantics/articletext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0104-66322015000200475en10.1590/0104-6632.20150322s00003371
institution SCIELO
collection OJS
country Brasil
countrycode BR
component Revista
access En linea
databasecode rev-scielo-br
tag revista
region America del Sur
libraryname SciELO
language English
format Digital
author Lima Neto,I. E.
spellingShingle Lima Neto,I. E.
SELF-SIMILARITY OF VERTICAL BUBBLY JETS
author_facet Lima Neto,I. E.
author_sort Lima Neto,I. E.
title SELF-SIMILARITY OF VERTICAL BUBBLY JETS
title_short SELF-SIMILARITY OF VERTICAL BUBBLY JETS
title_full SELF-SIMILARITY OF VERTICAL BUBBLY JETS
title_fullStr SELF-SIMILARITY OF VERTICAL BUBBLY JETS
title_full_unstemmed SELF-SIMILARITY OF VERTICAL BUBBLY JETS
title_sort self-similarity of vertical bubbly jets
description AbstractAn integral model for vertical bubbly jets with nearly monodisperse bubble sizes is presented. The model is based on the Gaussian type self-similarity of mean liquid velocity, bubble velocity and void fraction, as well as on functional relationships for initial liquid jet velocity and radius, bubble diameter and relative velocity. Adjusting the model to experimental data available in the literature for a wide range of densimetric Froude numbers provide constant values for the entrainment coefficient, momentum amplification factor, and spreading ratio of the bubble core for different flow conditions. Consistency and sensitivity of key model parameters are also verified. Overall, the deviations between model predictions and axial/radial profiles of mean liquid velocity, bubble velocity and void fraction are lower than about 20%, which suggests that bubbly jets tend to behave as self-preserving shear flows, similarly to single-phase jets and plumes. Furthermore, model simulations indicate a behavior similar to those of single-phase buoyant jets and slurry jets, but some differences with respect to confined bubbly jets are highlighted. This article provides not only a contribution to the problem of self-similarity in two-phase jets, but also a comprehensive model that can be used for analysis of artificial aeration/mixing systems involving bubbly jets.
publisher Brazilian Society of Chemical Engineering
publishDate 2015
url http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0104-66322015000200475
work_keys_str_mv AT limanetoie selfsimilarityofverticalbubblyjets
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