As part of the study of polymer, mixing, the deformation and break-up of a single drop suspended in a flowing fluid (or matrix) was studied. Combined unsteady shear and extensional flow were obtained for a matrix fluid forced through a convergence and then between parallel plates. Variation of drop sizes, viscosity ratios (viscosity of the solute/viscosity of the matrix), interfacial tension, initial position of the drop in the convergence were the parameters studied here.; Experiments were recorded on video to provide deformation measurements, velocity characteristics, drop asymmetry observations, and break-up mechanism pictures. Computational Fluid Dynamics (CFD) software was used to compute the velocity profiles in the complex experimental cell and to model drop deformation.; This study showed that deformation of Newtonian fluids is fairly easy to measure and behave accordingly to the viscosity ratios to the matrix. Computational results agreed well with the experimental. On the other hand viscoelastic fluids remained difficult to analyze. Several breakup modes were observed for different fluids and flow conditions. Droplet size and dispersion depended on the breakup mechanism.
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