Formation and Breakup of Bubbles and Drops

In this chapter we are concerned with the mechanisms and the underlying physics of the formation and breakup of bubbles and drops. The mechanisms for formation and breakup (or collapse) are fundamentally different depending on whether the processes involve phase change or not. In this context, we will discuss many processes which do not involve phase transitions, and two important processes which do involve phase change — bubble nucleation and droplet nucleation. Studies of formation and breakup are relevant to many important engineering applications. Most direct-contact heat and/or mass exchange equipment employ bubbles or drops in a suitable environment in order to enhance the rate of transport between the phases. The nucleation process for bubbles or droplets has to be understood to gain insight into boiling or condensation phenomena.