Ultrasonic phase velocity and attenuation in emulsions

Measurements of ultrasonic phase velocity and attenuation in emulsions have been carried out over a frequency range 250 kHz to 14 MHz for volume fractions of dispersed phase varying from 2% to 80%. The experimental data have been compared to theoretical predictions based on multiple scattering models. At volume fractions up to 50% a good agreement is found between experimental data of an oil-in-water emulsion and the theories. At volume fractions of dispersed phase above 50%, there are important discrepancies between the multiple scattering theories and the measurements on water-in-oil and oil-in-water emulsions. However, measurements on water-in-oil emulsions and attenuation in emulsions of aliphatic oils in water deviate considerably from the theories.