Trajectory of a spherical bubble rising in a fully developed laminar flow

Abstract

The rising trajectory of bubbles subjected to shear-induced lift force in a vertical channel is of great interest for designing and optimising a variety of electrochemical equipment. In this work, the rising trajectory of a spherical microbubble with a diameter of 0.3-1.0mm in a vertical channel with a fully developed laminar flow is investigated experimentally. Subsequently, the lift and drag forces on the bubble are assessed. Due to the limitation of the existing correlations for lift force coefficient, a new correlation is developed, which can be used to estimate the trajectory of a bubble in a vertical channel. The effect of flow velocity gradient and bubble diameter on the bubble motion is discussed to control bubble rising trajectory. It is concluded that the lift coefficient for a spherical microbubble in vertical channels with a fully developed laminar flow is slightly higher than the reported shear lift coefficient for larger bubbles rising in a high viscous liquid.