Three-dimensional study of single bubble dynamics and the surrounding flow field in a small diameter pipe by using particle tracking velocimetry

摘要

The capabilities of the particle tracking velocimetry technique to perform accurate measurements in two-phase flows are addressed int his paper. A hybrid of the particle tracking velocimetry and a shadow particle tracking velocimetry was employed to perform measurements of instantaneous velocity fields of the two components of a two-phase flow, in a Lagrangian approach. As an application of this hybrid technique, the flow field generated by a single air bubble freely rising in stagnant water in a small diameter pipe was described both qualitatively and quantitatively. Ensemble averaged mean and turbulent flow field, and the vorticity distribution were computed. The ensemble average operation was performed under the condition that the bubbles had a similar rising trajectory. A study of hte shape, trajectory, and rocking motion of the rising bubble was also considered.