Projeto de tanque e impelidor não convencional por ferramenta de CFD

Abstract

Inorganic scale have a negative impact on oil extraction, motivating studies to better understand its occurrence. The system chosen to reproduce this phenomenon was a tank without baffles agitated by an unconventional radial impeller, the MQ2021. Since these are new geometries, this work aims to perform a numerical analysis of the hydrodynamics inside the tank, to map the formation of vortexes, to compare the results of two-phase and single-phase simulations, to evaluate the influence of viewing windows on the flow, to characterize the impeller in terms of power number, pumping number and mixing time and compare it with the Rushton turbine. The simulations were carried out using ANSYS CFX v.15.0 choosing the SST komega model (Shear Stress Transport) as a closure to the turbulence and validated with the results of the article by Yoon, Balachandar and Ha (2009). The results showed that the adopted methodology was able to represent the velocity profiles generated by Yoon, Balachandar and Ha (2009). It was confirmed that single-phase simulations can be used to represent a two-phase system. The forced free surface vortex begins to form at 100 rpm. The observation windows had a positive impact on the system by directing part of the flow to the lower region of the tank, possibly improving the suspension of particles in that area. Comparing the MQ2021 with the Rushton turbine, the turbine generated a mass flow in the window 220% greater than MQ2021. In terms of mixing time, the values of the MQ2021 impeller and the turbine had a relative difference of approximately 7%. In the global parameters ( Np and Nq ), the MQ2021 proved to be more efficient and with greater pumping capacity than the turbine. Despite being impellers with different diameters, quantity, size and paddle thickness, with this analysis we have an overview of the behavior of this impeller in relation to other agitators commonly used in the field.