Relationship between interface motion of an isolated bubble and its zigzagging motion of the center of gravity

Abstract

The motion of the center of gravity and the interface motion of a bubble are essential for deep understanding of the mass transfer mechanism between gas and liquid phases in a bubble column, a gas-lift reactor, and so on. Since the two-phase flows have the hierachical structure, the interaction between the interface motion of the individual bubbles and the local-scale motion of the surrounding liquid plays a role important for the mass transfer process in the vicinity of their surfaces. In the present study, the interrelation between the motion of the center of gravity and the interface motion of a zigzag rising bubble in rest water has been investigated. The bubble of 2.64 mm in equivalent diameter was microscopically visualized by high-speed video camera, in order to catch minute interface motion. Statistical analysis of the bubble interface motion has been achieved by maintaining the high reproducibility of bubble release with a hypodermic needle. Analyzing the fluctuation of the curvature in right-and-left bubble shape edges, the relationship between the asymmetrical interface motion and the zigzagging motion was elucidated.