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Experimental study of bubble-drag interaction in a Taylor-Couette flow

Fokoua, Georges and Gabillet, Céline and Colin, Catherine Experimental study of bubble-drag interaction in a Taylor-Couette flow. In: 8th International Conference on Multiphase Flow ICMF 2013, 26 May 2013 - 31 May 2013 (Jeju Island, Korea, Republic Of).

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Abstract

This study is an experimental investigation of the interactions between the bubbles, the coherent motion and the viscous drag in a Taylor Couette flow, for the outer cylinder at rest. The cylinder radius ratio η is 0.9. Bubbles are injected through a needle at the bottom of the apparatus inside the gap. Different bubble sizes are investigated (ratio between the bubble size and the gap width 0.05 and 0.12) for very small void fraction(α≤0.012). Different flow regimes are studied corresponding to Reynolds number Re based on the gap width and the velocity of the inner cylinder ranging from 400 to 20000. For these Re values, Taylor vortices are persistent leading to an axial periodicity of the flow. PIV measurements of the liquid flow features, bubble tracking in a meridian plane and viscous torque of the inner cylinder measurements are performed. This study provides a first evidence of the link between the bubble localisation, the Taylor vortices and viscous torque modifications. Bubbles are attracted towards the inner cylinder, due to the rotation of the cylinder. For small buoyancy effect, bubbles are trapped and induce a decrease in the outflow intensity, thus leading to an increase of the viscous torque. When buoyancy induced bubble motion, by comparison to the coherent motion of the liquid is increased, a decrease in the viscous torque is suspected.

Item Type:Conference or Workshop Item (Paper)
HAL Id:hal-00973223
Audience (conference):International conference proceedings
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Other partners > Ecole Navale (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Laboratory name:
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Deposited By: Catherine COLIN
Deposited On:04 Apr 2014 08:16

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