Measurements of bimodal droplet size distribution of emulsions using ultrasonic spectroscopy in the long and intermediate wavelength regimes

Abstract

Ultrasonic spectroscopy has a great potential to measure the particle sizes in suspensions and emulsions of many industrial sectors. However, one significant challenge is measuring particle sizes in a broader range and concentrated systems due to the lack of theoretical models covering large particle wave-particle interaction mechanisms. An alternative way lies with the simultaneous application of ultrasonic theories that operate in long and intermediate wavelength regimes. This work used acoustic spectroscopy to measure size droplets of water-in-sunflower oil emulsions for a volume concentration range of 10 to 50% considering bimodal distributions. The observed attenuation spectra results were compared with the simplest acoustic models applied for the long and intermediate wavelength regimes. The results of ultrasonic spectroscopy agreed with those obtained by laser diffraction and indicate that the methodology used in this study is suitable to measure bimodal droplet distributions with diameters from 0.1 to 1000 μm and concentrations up to 40% vol.