Velocities of acoustic streaming in a solid-liquid mixture generated by an ultrasonic wave (Particles and particle concentration)

Abstract

Progressive ultrasonic waves cause acoustic streaming in a liquid. Although theoretical and experimental studies on acoustic streaming for liquid phase have been carried out, acoustic streaming for a solid-liquid mixture does not seem to have been investigated. The purpose of this study is to clarify the velocity distribution of acoustic streaming in a solid-liquid mixture. An ultrasonic wave with a frequency of 485 kHz was horizontally irradiated on tap water with aluminum particles in a cylindrical tube with a diameter of 120 mm whose orientation was kept horizontal; the acoustic streaming velocities were measured with the irradiation time of the ultrasonic wave, initial particle concentration, and particle shape as the parameters. The following results were obtained: (a) The higher the initial particle concentration is, the faster the acoustic streaming velocity of a solid-liquid mixture becomes; (b) When ultrasonic waves are irradiated on a liquid with heavier solid particles, the acoustic streaming velocity of the solid-liquid mixture decreases with irradiation time to a certain extent.