1. Experimental investigation of heat transport in inhomogeneous bubbly flow
- Author
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Dennis P. M. van Gils, Biljana Gvozdić, Elise Alméras, Sander G. Huisman, Chao Sun, Detlef Lohse, On Yu Dung, University of Twente [Netherlands], Laboratoire de génie chimique [ancien site de Basso-Cambo] (LGC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Tsinghua University [Beijing] (THU), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Tsinghua University (CHINA), University of Twente (NETHERLANDS), Laboratoire de Génie Chimique - LGC (Toulouse, France), Physics of Fluids, and Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
- Subjects
Work (thermodynamics) ,Materials science ,Buoyancy ,General Chemical Engineering ,Flow (psychology) ,Mixing (process engineering) ,UT-Hybrid-D ,FOS: Physical sciences ,02 engineering and technology ,engineering.material ,Industrial and Manufacturing Engineering ,Physics::Fluid Dynamics ,[CHIM.GENI]Chemical Sciences/Chemical engineering ,020401 chemical engineering ,Heat transfer ,Génie chimique ,[SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering ,0204 chemical engineering ,Génie des procédés ,Bubbly flows ,Turbulence ,Applied Mathematics ,Fluid Dynamics (physics.flu-dyn) ,Physics - Fluid Dynamics ,General Chemistry ,Rayleigh number ,Mechanics ,021001 nanoscience & nanotechnology ,Volumetric flow rate ,engineering ,0210 nano-technology ,Experiments ,Bubble column - 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 $\alpha = 0.4\% - 5.1 \%$, and the Rayleigh number $Ra_H=4\times10^9-2.2\times10^{10}$. 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: (\textit{i}) transport by the buoyancy driven recirculation, (\textit{ii}) bubble induced turbulence (BIT) and (\textit{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 Gvozdi{\'c} \emph{et al.} (2018). We find that for the lower gas volume fractions ($\alpha4\%$, when the contribution of SIT becomes stronger, but so does the competition between all three contributions, the homogeneous injection is more efficient.
- Published
- 2019