Particle Image Velocimetry In A Centrifugal Pump: Influence Of Walls On The Flow At Different Axial Positions

Abstract

Abstract For almost a century, humans have relied on pumps for the transport of low-viscous fluids in commercial, agricultural, industrial activities. Details of the fluid flow in impellers often influence the overall performance of the pump, and may explain unstable and inefficient operations taking place sometimes. However, most studies in the literature were devoted to understanding the flow in the mid-axial position of the impeller, only a few focusing their analysis on regions closer to solid walls. This paper aims at studying the water flow on the vicinity of the front and rear covers (shroud and hub) of a radial impeller to address the influence of these walls on the fluid dynamics. For that, experiments using particle image velocimetry (PIV) were conducted in a transparent pump at three different axial planes, and the PIV images were processed for obtaining the average velocity fields and profiles, and turbulence levels. Our results suggest that: significant angular deviations are observed when the velocity vectors on peripheral planes are compared with those on the central plane; the velocity profiles close to the border are similar to those in the middle, but the magnitudes are lower close to the hub than to the shroud; the turbulent kinetic energy on the periphery is eight times greater than that measured at the center. Our results bring new insights that can help proposing mathematical models and improving the design of new impellers. A database and technical drawings of the centrifugal pump are also available in this paper.