Chemical Engineering Communications, Vol.202, No.9, 1251-1260, 2015
Viscous Filament Fragmentation in a Turbulent Flow Inside a Stirred Tank
The present work describes the dispersion process of a viscous fluid in water in a cylindrical vessel agitated at Re = 24,000. The formation of viscous filaments and other amorphous structures in turbulent conditions produced in the early stage, before oil drops saturate the continuous phase, is shown. The oil-phase evolution is followed with high-speed video recordings and compared with the flow pattern produce in the liquid bulk. The effects of four kinds of perturbations are identified: intermittences in the radial velocity, turbulent fluctuations, rotation, and the stretching. As a consequence, the viscous-phase experiences instabilities that include random deformation, elongation, hairpin filaments formation, folding, and fragmentation. In the final part of this study, a mechanism describing the drop size reduction has been proposed.