Investigation on Effect of Flow Direction on Hydrodynamics for vertical Channel Bubbly Flow

Abstract

In order to fully understand hydrodynamics of the bubbly flow laden with microbubbles, the effect of flow direction on the phase distribution and the liquid–phase turbulence modulation in a vertical channel flow laden with microbubbles was detailedly investigated with a developed numerical method, where the liquid–phase velocity field was solved by direct numerical simulations and the microbubble trajectories were tracked by Newtonian equations of motion. The present investigations show the flow direction has the key influence on the phase distribution and the liquid–phase turbulence modulation; for the bubbly upflow, the overwhelming majority of microbubbles accumulate near the channel wall, the phase distribution display approximately the double–peaked distribution patter, and the liquid–phase turbulence was suppressed; for the bubby downflow, however, the microbubbles are far away from the channel wall to move towards the channel centre, the phase distribution shows roughly the off–center–peaked distribution pattern, and the liquid–phase turbulence was enhanced.