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Turbulent bubbly flow in pipe under gravity and microgravity conditions

Colin, Catherine and Fabre, Jean and Kamp, Arjan Turbulent bubbly flow in pipe under gravity and microgravity conditions. (2012) Journal of Fluid Mechanics, 711. 469-515. ISSN 0022-1120

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Official URL: http://dx.doi.org/10.1017/jfm.2012.401

Abstract

Experiments on vertical turbulent flow with millimetric bubbles, under three gravity conditions, upward, downward and microgravity flows (1g, -1g and 0g), have been performed to understand the influence of gravity upon the flow structure and the phase distribution. The mean and fluctuating phase velocities, shear stress, turbulence production, gas fraction and bubble size have been measured or determined. The results for 0g flow obtained during parabolic flights are taken as reference for buoyant 1g and -1g flows. Three buoyancy numbers are introduced to understand and quantify the effects of gravity with respect to friction. We show that the kinematic structure of the liquid is similar to single-phase flow for 0g flow whereas it deviates in 1g and -1g buoyant flows. The present results confirm the existence of a two-layer structure for buoyant flows with a nearly homogeneous core and a wall layer similar to the single-phase inertial layer whose thickness seems to result from a friction–gravity balance. The distributions of phase velocity, shear stress and turbulence are discussed in the light of various existing physical models. This leads to a dimensionless correlation that quantifies the wall shear stress increase due to buoyancy. The turbulent dispersion, the lift and the nonlinear effects of added mass are taken into account in a simplified model for the phase distribution. Its analytical solution gives a qualitative description of the gas fraction distribution in the wall layer.

Item Type:Article
Additional Information:Thanks to Cambridge University Press. The definitive version is available at http://dx.doi.org/10.1017/jfm.2012.401
HAL Id:hal-00875768
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)
Other partners > Total (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Laboratory name:
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Deposited By: Catherine COLIN
Deposited On:22 Oct 2013 14:41

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