Application of acoustic techniques to fluid-particle systems - A review

Acoustic methods applied to opaque systems have attracted the attention of researchers in fluid mechanics. In particular, owing to their ability to characterise in real-time, non-transparent and highly concentrated fluid-particle systems, they have been applied to the study of complex multiphase flows such as fluidised beds. This paper gives an overview of the physical principles and typical challenges of ultrasound and acoustic emission AE methods when applied to fluid-particle systems. The principles of ultrasound imaging are explained first. The measurement techniques and signal processing methodologies for obtaining velocity profiles, size distribution of the dispersed phases, and solid volume frac-tion are then discussed. The techniques are based on the measurement of attenuation, sound speed, frequency shift, and transit time of the propagated sound wave. A descrip-tion of the acoustic emission technique and applications to fluid-particle systems are then discussed. Finally, extensions and future opportunities of the acoustic techniques are pre-sented. Crown Copyright (c) 2021 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers. All rights reserved.

Automated summary

This paper provides an overview of the application of acoustic methods to fluid-particle systems, including ultrasound imaging and acoustic emission techniques. By measuring different properties of propagated sound waves, information such as velocity distribution and particle size distribution in fluid-particle systems can be obtained.