Bubble dynamics in two-phase flows around cylinders
- Univ. of Cambridge (United Kingdom). Dept. of Chemical Engineering
Bubble dynamics in two-phase flow around a circular cylinder are examined experimentally for cylinder Reynolds numbers in the subcritical range. Streaklines of air bubbles in a vertical water downflow around a cylinder are visualized. Bubble dispersion in the wake region of the cylinder is observed to be controlled by the transient large scale turbulent structures formed as a result of vortex shedding. Bubbles are trapped in the near wake behind the cylinder and advected downstream within these shed vortices. A theoretical model is proposed to simulate bubble trajectories in a non-uniform and transient liquid velocity field. The unsteady flow field around the cylinder is simulated using a discrete vortex method and bubble trajectories are calculated by integrating a Lagrangian equation of motion for a single bubble through this flow field. The numerically obtained bubble streaklines are very similar to those observed experimentally. The controlling nature of the unsteady large scale vortex structure of the flow indicates that time-averaged simulation are not suitable for modeling bubbly flows in the wake region.
- OSTI ID:
- 94459
- Report Number(s):
- CONF-940659--; ISBN 0-7918-1377-6
- Country of Publication:
- United States
- Language:
- English
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