Imperial College London
Alternate

ProfessorChristosMarkides

Faculty of Engineering, Department of Chemical Engineering

Professor of Clean Energy Technologies
 
 
 
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Contact

 

+44 (0)20 7594 1601c.markides Website

 
 
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Location

 

404ACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Moran:2021:10.1016/j.ijmultiphaseflow.2020.103468,
author = {Moran, HR and Magnini, M and Markides, CN and Matar, OK},
doi = {10.1016/j.ijmultiphaseflow.2020.103468},
journal = {International Journal of Multiphase Flow},
pages = {1--13},
title = {Inertial and buoyancy effects on the flow of elongated bubbles in horizontal channels},
url = {http://dx.doi.org/10.1016/j.ijmultiphaseflow.2020.103468},
volume = {135},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - When  a  long  gas  bubble  travels  in  a  horizontal  liquid-filled  channel  of  circular  cross-section, a liquid film is formed between the bubble and the channel wall.  At low Reynoldsand Bond numbers, inertial and buoyancy effects are negligible, and the liquid film thicknessis a function of the capillary number only.  However, as the tube diameter is increased to themillimetre scale, both buoyancy and inertial forces may become significant.  We present theresults of a systematic analysis of the bubble shape,  inclination,  and liquid film thicknessfor a wide range of capillary, Bond, and Reynolds numbers, namely 0.024≤Cal≤0.051,0.11≤Bo≤3.5, and 1≤Rel≤750.  Three-dimensional numerical simulations of the floware performed by employing the Volume-Of-Fluid method implemented in OpenFOAM. Inagreement with previous studies, we observe that buoyancy lifts the bubble above the chan-nel axis, making the top liquid film thinner, and thickening the bottom film.  As the Bondnumber approaches unity, the cross-sectional shape of the bubble deviates significantly froma circular shape,  due to flattening of the bottom meniscus.  The simulations demonstratethe existence of a cross-stream film flow that drains liquid out of the top film and drives ittowards the bottom film region.  This drainage flow causes inclination of the bubble, witha larger inclination angle along the bottom plane of the bubble than the top.  As buoyancybecomes even more significant, draining flows become less effective and the bubble inclina-tion reduces.  A theoretical model for the liquid film thickness and bubble speed is proposedembedding dependencies on both capillary and Bond numbers, which shows good agreementwith the reported numerical results.  Inertial forces tend to shrink the bubble cross-sectionand further lift the bubble above the channel centreline, so that the bottom film thicknessincreases significantly with the Reynolds number, whereas the top film thickness is less
AU  - Moran,HR
AU  - Magnini,M
AU  - Markides,CN
AU  - Matar,OK
DO  - 10.1016/j.ijmultiphaseflow.2020.103468
EP  - 13
PY  - 2021///
SN  - 0301-9322
SP  - 1
TI  - Inertial and buoyancy effects on the flow of elongated bubbles in horizontal channels
T2  - International Journal of Multiphase Flow
UR  - http://dx.doi.org/10.1016/j.ijmultiphaseflow.2020.103468
UR  - https://www.sciencedirect.com/science/article/pii/S0301932220305796?via%3Dihub
UR  - http://hdl.handle.net/10044/1/85070
VL  - 135
ER  -
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