Concurrent Bubbly Flow in Large Diameter Vertical Pipe

This book is intended for engineering graduate students and Research and Development scientists who are interested in liquid and gas flows and the mutual interaction between the gas bubbles and the surrounding liquid turbulence field. In this study, air-water bubbly flow in a 200 mm diameter vertical pipe was experimentally investigated. A dual optical probe is used to measure the bubble characteristics, while the liquid turbulence characteristics are measured using hot-film anemometers. Results showed that bubbles tended to migrate toward the pipe centreline, which is different than small diameter pipes. Turbulence suppression was observed near the pipe wall at low void fraction flows. The balance between the lift and the turbulent dispersion forces is studied and a non-dimensional map between these parameters and the force ratio is proposed to characterize the flow conditions that govern the phase distribution in both of small and large diameter pipes. The effect of the bubbles on the liquid turbulence kinetic energy is investigated and a model for the spectral bubble production is introduced to explain the turbulence suppression phenomenon.