Breakup and coalescence in turbulent two-phase flows

• Main Author: Hunt, William E.
• Other Authors: Mechanical Engineering
• Format: Others
• Language: en
• Published: Virginia Tech 2014
• Subjects: turbulent flow; LD5655.V855 1995.H8345
• Online Access: http://hdl.handle.net/10919/40633; http://scholar.lib.vt.edu/theses/available/etd-01172009-063113/

Many engineering processes involve a gas and a liquid or two immiscible liquids in turbulent flow. The turbulent flows present in two-phase systems will cause the bubbles or drops of a dispersion to undergo breakup and coalescence, and the resulting changes in the dispersion may significantly affect the engineering process under consideration. For this reason, many researchers have studied breakup and coalescence in turbulent two phase flows. Models that can be used to simulate changes in a dispersion over time have been proposed, but these models contain constants that change with experimental conditions and empirical equations that can only be considered valid for certain experimental setups. The goal of this study was to develop general models that could be used to predict changes in bubble or drop size distributions over time for turbulent flows in agitated vessels and pipes. <p>Computer programs were written to reproduce the results of three agitated vessel studies. These programs used existing population balance models to approximate the changes in a dispersion over time measured in previous experiments. A new model for breakup in agitated vessels was then developed and verified with existing experimental data. A new model for coalescence in agitated vessels was also developed and verified with existing experimental data. Both of these models are based on theory and are more readily extendible than previous breakup and coalescence models. The work for agitated vessels was then extended to turbulent two-phase pipe flow. Since there was only a limited amount of experimental data available for breakup and coalescence in pipes, the model for turbulent pipe flow could not be verified. === Master of Science