Positron emission particle tracking and CFD investigation of hydrocyclones acting on liquids of varying viscosity

摘要

Cyclone separators are widely used for separation of solids or droplets from gases or liquid fluids. They represent an elegant and robust separation technology involving low capital and maintenance costs. It is therefore interesting, to extend cyclone technology to new applications, particularly in the oil and gas industry where separation duties are becoming ever more demanding and diverse, and separation processes are moving to more remote installations, such as sub-sea or even down-hole installations. The objective of this paper is to elucidate the working of hydrocyclones including ones acting on liquids of elevated viscosity using state-of-the-art experimental and analysis techniques, namely positron emission particle tracking (PEPT) and computational fluid dynamics (CFD) with large-eddy simulation of turbulence effects. The results show a number of interesting and anomalous features of the liquid and particle flow, such as unexpected excursions of particles to the inner vortex and the effect of the vortex end on the particle flow. It is shown that it is possible to determine the axis of the hydrocyclone very precisely by a minimization technique and thus convert the output from the tracking algorithm in Cartesian coordinates to cylindrical coordinates with the cyclone as axis. This throws additional light on the results. Tracks of different particles, some of which are eventually captured and some which are lost, are shown both in 3-D Cartesian and 2-D cylindrical coordinates and the effects of the fluid and particle properties are discussed. (C) 2019 Elsevier Ltd. All rights reserved.