Effect of Particle Size Distribution on Erosion Wear in Centrifugal Pump Casings

Abstract

The aim of this paper is to study the effect of particle size distribution on erosion rate characteristics in pump casings. The typically broad particle size distribution (PSD) found in industrial slurries is viewed in terms of a discrete number of size classes, each with a representative diameter. An Eulerian-Eulerian mixture model is used to compute the two-dimensional flow field and particle concentration distribution inside a pump casing. Erosion wear due to particle impact and sliding abrasion is then calculated using empirically determined (particle-size dependent) wear rate coefficients to relate the erosion wear to the local flow field properties. Wear rate predictions are compared for (a) multi-size, (b) D50 mono-size of the slurry, (c) the concentration-weighted mono-size, and (d) the average of D50 and D85 sizes. Depending on the operating conditions, the four predictions differ from one another, indicating that adjustments to mono-size predictions are essential to capture the effect of the PSD. Parametric study is performed to analyze the effect of the flow operating conditions, inlet particle concentration and PSD on the prediction of wear rates along the casing wall.Copyright © 2013 by ASME