VISUALIZATION AND MODELING OF VISCOELASTIC DROP DEFORMATION AND BREAKUP IN SIMPLE SHEAR FLOW

摘要

The deformation and breakup of Boger-fluid drops in Newtonian liquids under simple shear flow were investigated by direct visualization using a specially designed Couette apparatus which enables visualization from two different directions (i.e. to get a 3-D image). Four types of breakup modes were observed. Boger-fluid drops can break up in simple shear flows along the flow axis or the vorticity axis. The breakup mode was found to depend on drop size, viscosity ratio, interfacial tension, matrix viscosity and drop phase viscoelasticity.