General Aspects of Phase Morphology Development

The pioneering work of Taylor on drop break-up in Newtonian systems in a simple shear field has been the basis of investigations on more complex systems and flow fields [40, 41]. The analysis of Taylor considers how the balance of applied shear forces and counteracting interfacial forces affects drop dimensions and stability. The results have been expressed in terms of the so-called capillary number, 

Wu s correlation suggests a minimum particle size when the viscosities of the two phases are closely matched. The validity of this equation has been testified by researchers [27,47] who have indicated some disagreement with respect to the dependence of the particle size on viscosity ratio and the correlation proposed by Wu. On the other hand, Serpe et al. [22] found a good agreement of their experimental observations with Wu s results. An experimental minimum in the dispersed phase size with increasing shear rate was reported in the literature and this has been explained based on the high elasticity of the droplet and the resulting resistance to deformation at increased shear rates [48], 

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