Estudo numérico do escoamento de fluido de bingham em contração abrupta

Abstract

The non-Newtonian fluids are present in many different industrial sectors, where there is an special application in the polymers, food, pharmacy na oil industries. To study this kind of fluid, it must be used a viscosity model different to the one that we use for Newtonian fluids. In the present work, we use the model of the Generalized Newtonian Fluid – GNF – which is widely diffused in the scientific community. The aim of this work is the numerical study of the viscoplastic non Newtonian fluids laminar flow through abrupt contractions of different contractions rate. The geometry of an abrupt contraction, despite of being quite simple, does not allow an analytical solution for the flow, what makes the numerical simulations extremely necessary to the study. The software used in the simulations is Polyflow. As hypothesis for the study, we assume that the flow is incompressible, in laminar flow, isothermal, with constant properties and in steady state. As results, we will discuss the pressure fields, stream lines, regions with no shear-rate, velocity fields and the adimensional pressure loss as function of the adimensional parameters Reynolds and Hedstrom. By the simulations, we could observe that the contraction rate does not change the flows pattern after the change of diameter. Furthermore, the adimensional pressure loss is not a function of the contraction rate as well.