Chapter One – Hydrocyclones

This chapter gives a brief synopsis of hydrocyclones in theory and in practice, including basic design, characterization of performance, models, scale-up and design, as well as monitoring and control of the equipment. The effect of various operational variables, such as pressure drop, cone angle, cyclone diameter, vortex finder and spigot diameters, and solids concentration in the feed on the throughput, cut size, and sharpness of classification of hydrocyclones, is summarized. Both fundamental and empirical models are considered. Numerical solution of first principles models is discussed, with different turbulence models, such as Reynolds averaged Navier–Stokes (RANS) models, large eddy simulation (LES) models, and direct numerical simulation (DNS) models. The Plitt model is considered as a widely used example of empirical models. As an example of the online monitoring of hydrocyclones, the analysis of videographic images of the underflow is discussed, as previously proposed in the literature. This includes the extraction of spray profile variables from image data and online mapping of the data to a process chart, where the normal operating region is delineated by contours following the density.