Experimental quantification of turbulence and its applications in the study of multiphase flotation pulps

Abstract

Turbulence is common in daily activities, both naturally and industrially. However, it is not well understood on the microscopic level because there is a lack of suitable quantification techniques especially for multi-phase particulate systems such as flotation pulps. In this paper, the different quantification techniques which have been used to characterise turbulence in the literature have been reviewed in terms of their basic principles, system structure, the range of application and limitations. Optical techniques such as Laser Doppler Anemometry and Particle Image Velocimetry can produce accurate measurement results with high spatial and temporal resolution, but their applications are limited to transparent flows. Hot wire probes have high spatial and temporal resolution in turbulence quantification, but they are susceptible to environmental factors. Conductivity probe, Electrical Resistance Tomography (ERT) and piezoelectric sensor are techniques that can quantify turbulence in multiphase flows, but their spatial resolutions are limited. Particle Tracking Velocimetry can reveal particle trajectories in multiphase flows; it can also measure velocity fluctuation. Positron Emission Particle Tracking cannot be used to quantify turbulence although it can also be used to determine the Lagrangian trajectory of particles. For turbulence quantification in three phase flows, piezoelectric sensor, ERT and conductivity probe require further development.