ABSTRACT
The devolatilization of polymeric systems entails the expansion of bubbles by molecular diffusion of the solvent. Boiling of non-Newtonian polymer solutions and suspensions involves the nucleation and growth/collapse of bubbles. The mass, momentum, and energy transport in the context of bubble phenomena in stagnant and/or moving liquids which exhibit complex rheological behavior is central to the understanding of the various applications. The shape of a bubble not only influences its free-rise velocity but also plays an important role in determining the rates of heat and mass transfer and coalescence. In Newtonian fluids, small bubbles are known to display solid-sphere-like behavior and the transition from a no-slip to a zero-shear condition is fairly gradual. In applications involving relative motion between gas bubbles and a stagnant/moving liquid, the residence time of the gas is a key parameter which, in turn, depends on the free-rise velocity and the height of the equipment or liquid column.
