Flow and Surface Renewal of the Viscous Filaments in a High-Speed Disperser

High-speed rotating equipment can be used in the devolatilization of high-viscosity polymer fluids, where the surface renewal is regarded as an important factor on mass transfer. In this work, based on the verification of computational fluid dynamics simulation with the flow visualization experiment, the width, residence time, and velocity of the filament from a rotor were studied by the volume of fluid model, including the influence of rotational speed, fluid viscosity, and surface tension, and so forth. A surface renewal stretch model was built to acquire the surface renewal rate (S-p). The results show that S-p, along the stretching direction of the filament generally reaches a maximum value as soon as it is formed, while S-p decreases sharply in a relatively short distance. The Reynolds number and Weber number of the rotor together with the radial distance were used to describe S-p under various conditions for the evaluation of mass transfer performance of such high-speed dispersers.