EXPERIMENTAL STUDY OF THE FLOW DYNAMICS OF COMPLEX VISCOELASTIC FLUID THROUGH HYPERBOLIC CONTRACTION/EXPANSION

The main objetive of this work was to experimentally study the Flow dynamics of viscoelastic fluids (Boger fluid and Hase) when they flow through a contraction/expansion system defined by a hyperbolic tube, therefore through equations analogous to the Hagen-Poiseuille equation, the pressure drop associated with the viscous interaction was quantified, and subsequently the excess pressure drop (EPD), a parameter associated with the elasticity of viscoelastic fluids, conducting comparative studies with respect to a Newtonian reference for the same shear viscosity value, which allowed observing shear speed intervals where three predominant zones were observed. The first of them of shear type coinciding with the trajectories of the Newtonian fluid of identical viscosity value, the second zone was attributed to the elastic manifestation of the fluids due to the preferential development of the extensional flow that is in constant competition with the shear flow within of the same geometry. The third zone was attributed to a predominance of the shear flow over the extensional one, because of to the fact that the hyperbolic geometry favors the development of this type of flow at high values of shear rate KEYWORDS: Excess pressure drop; Extensional flow; Hyperbolic contractions