Produzione di gocce di olio in liquidi non newtoniani con una giunzione a T

The goal of this thesis is to study oil droplets production in viscoelastic non newtonian fluids in a T junction microfluidic device. In particular it has been studied a Boger fluid. These fluids mantain their viscosity constant with shear rate variations, as newtonian fluids do, and at the same time they exhibit properties and effects similar to the ones observed for elastic matter. To do this, two fluids (a newtonian one and a Boger one) with similar properties have been used for direct comparation and to see possible elastic effects. Direct measures on lenght and production rate of droplets have been made at various flux ratios (the ratio between the dispersed phase and continuous phase flow ratios) and capillary numbers (an adimensional number which quantifies the magnitude of viscous forces over capillary ones in the system). It has been made also an indirect measure of droplets volume. The results of this preliminary study suggest that the Boger fluid behaves like a newtonian fluid of equal viscosity. The only noticed difference appears in the more stretched shape of the droplets at lower flux ratios.