Ultrasound Attenuation Analysis of Liquid-Solid Mixtures with Multi-Frequency Ultrasound Excitation

Ultrasound method is widely used in liquid-solid two-phase system for flow parameter measurement. Ultrasound attenuation characteristic of the two-phase mixed system has a strong relationship with the solid phase fraction, mixture density, and particle size distribution in the mixing process. This paper presents a multi-frequency ultrasound excitation method combined the multiple single frequency and chirp signals to investigate the ultrasound attenuation under different solid phase distribution, phase fraction, particle size distribution. The solid particles are polymethyl methacrylate with diameter of 1.5, 2, 2.5, 3 mm and density of 1.18 g/cm(3), and the liquid phase is tap water with density of 1g/cm(3). The ultrasound frequency ranges from 1 to 5 MHz and the transducers work at the Pitch-catch mode. The experimental results show that the ultrasound attenuation coefficient increases with the solid phase fraction under both homogeneous and heterogeneous liquid-solid mixtures. The attenuation coefficient of the heterogeneous mixtures is higher than that of the homogeneous at the same solid fraction in the present study.