The growth of a single rising bubble in viscous solution and the resulting volatile removal

Abstract

In the foam devolatilization, volatiles are removed accompanying with the growth of rising bubbles, and determining the amount of removed volatile is important in the design of devolatilization device. In this work, acetone and polydimethylsiloxane were used as the volatile and polymer respectively to study the single bubble growth process in the foam devolatilization. The variation of single bubble spherical equivalent radius and rising velocity in viscous solution were experimentally determined, and the effects of operational parameters (i.e., polymer viscosity, vacuum degree, solution temperature and volatile concentration) on bubble growth were evaluated. By analyzing the mechanics of bubble devolatilization, and based on the mass transfer boundary layer theory, the mass of removed volatile during bubble rising is determined, together establishing a correlation to predict the volatile removal amount.