Otimização computacional de hidrociclone na irrigação pressurizada.

Abstract

The use of low quality water with high presence of sediments, has become common in irrigated agriculture and also a big problem. To minimize these problems, hydrocyclones have been increasingly used in irrigation systems because they are easy to construct and require low maintenance. Within this context, the objective of this work was optimize the performance of a hydrocyclone used in irrigation, in other words, obtain maximum separation efficiency of sediments with lower pressure drop. The efficiency and drop pressure were investigated using simulations in computational fluid dynamics (CFD) in this package ANSYS® CFX® 13. The turbulent flow is modeled using the model Reynolds Stress Model and multiphase flow is modeled using an Eulerian approach. The numerical validation is done by comparing simulation results with data from the literature. A correlation study investigates the influence o f six geometrical and two operational variables in separation efficiency and pressure drop of the hydrocyclone. They are: feeding diameter, tube diameter of diluted, diameter of the exit orifice of concentrated suspension, length of the cylindrical part, length o f diluted tube, length of cone and density and concentration of solids in the feed. The study shows that the diameter of feed, the diameter of diluted tube and diameter of the exit hole of the concentrated suspension are the parameters that influence the performance of the hydrocyclone. With these three parameters, an experimental design with fifteen different geometries was evaluated and an optimal geometry was identified. The optimized geometry provided a 31,45 % increase in separation efficiency and a reduction of 8,87 % in pressure drop compared to the base hydrocyclone. With these results, it is possible show that the methodology used allow to analyze the main parameters involved in the optimization of hydrocyclones and at the same time allowing the identification o f a geometry that optimize the performance within the range of parameters.