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Experimental investigation of heat transport in homogeneous bubbly flow

Gvozdić, Biljana and Alméras, Elise and Mathai, Varghese and Zhu, Xiaojue and van Gils, Dennis P. M. and Verzicco, Roberto and Huisman, Sander G. and Sun, Chao and Lohse, Detlef Experimental investigation of heat transport in homogeneous bubbly flow. (2018) Journal of Fluid Mechanics, 845. 226-244. ISSN 0022-1120

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Official URL: https://doi.org/10.1017/jfm.2018.213

Abstract

In this work we study the heat transport in inhomogeneous bubbly flow. The experiments were performed in a rectangular bubble column heated from one side wall and cooled from the other, with millimetric bubbles introduced through one half of the injection section (close to the hot wall or close to the cold wall). We characterise the global heat transport while varying two parameters: the gas volume fraction , and the Rayleigh number . As captured by imaging and characterised using Laser Doppler Anemometry (LDA), different flow regimes occur with increasing gas flow rates. In the generated inhomogeneous bubbly flow there are three main contributions to the mixing: (i) transport by the buoyancy driven recirculation, (ii) bubble induced turbulence (BIT) and (iii) shear-induced turbulence (SIT). The strength of these contributions and their interplay depends on the gas volume fraction which is reflected in the measured heat transport enhancement. We compare our results with the findings for heat transport in homogeneous bubbly flow from Gvozdić et al. (2018). We find that for the lower gas volume fractions (), inhomogeneous bubbly injection results in better heat transport due to induced large-scale circulation. In contrast, for , when the contribution of SIT becomes stronger, but so does the competition between all three contributions, the homogeneous injection is more efficient.

Item Type:Article
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Other partners > Tsinghua University (CHINA)
Other partners > Università degli Studi di Roma "Tor Vergata" (ITALY)
Other partners > University of Twente (NETHERLANDS)
Laboratory name:
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Deposited By: Loetitia MOYA
Deposited On:12 Dec 2018 10:02

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