Eur. Phys. J. B 4, 379-386 (1998)
https://doi.org/10.1007/s100510050393

II. Recirculation flow induced by a bubble stream rising in a viscous liquid

Institut de Science et de génie des matériaux et procédés (UPR 8521.) , BP 5, 66125 Font-Romeu, France

Corresponding author: ^a snabre@imp-odeillo.fr

Received: 23 July 1997
Revised: 19 December 1997
Accepted: 11 May 1998
Published online: 15 August 1998

Abstract

The recirculation flow induced by the rising motion of a bubble stream in a viscous fluid within an open-top rectangular enclosure is studied. The three-dimensional volume averaged conservation equations are solved by a control-volume method using a hybrid finite differencing scheme to describe the liquid phase hydrodynamics. The momentum exhange between the bubbles and the liquid phase is modeled with a source term equals to the volumetric buoyancy force acting on the gas in the bubble stream. The volumetric buoyancy force accounts for in line interactions between bubbles through the average gas volume fraction in the gas liquid column which depends on the size and the rising velocity of bubbles. The fluid flow within an open-top rectangular enclosure is further investigated by particle image velocimetry for a bubble stream rising in a water-glycerol solution. The measured fluid velocities in a vertical plane are compared with the predictions of the numerical model over a wide range of fluid viscosity (43 mPa s-800 mPa s) and gas flow rates. Finally, the recirculation flows resulting from the interaction of two neighbouring vertical bubble streams are studied.