Velocity Field Measurement during Coalescent Procedure of Two Rising Bubbles in a Pipe

Abstract

Bubbles are generated at a bottom nozzle and travel upward. They coalesce at a certain distance from the nozzle. Motion of the bubbles and velocity field in a vertical cylindrical liquid column are measured combining new visualization techniques and a PTV Technique. Velocity field around the bubbles changes with this chasing process quantitatively.
The Reynolds number based on a bubble diameter is 0.2, a diameter ratio to the experimental pipe is about 0.25.