Title: Simulation of ultrasonic attenuation in the elastic mixing particle system

Author(s): LI Yunsi; SU Mingxu; YANG Huinan; FAN Fengxian; CAI Xiaoshu;

Affiliation(s): Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, University of Shanghai for Science and Technology

Abstract: For the study of predicting ultrasonic attenuation of elastic, spherical mixing particles in the liquid-solid two-phase system, the Monte Carlo method(MCM) is introduced, serving as a probability and statistics technique to evaluate the inside ultrasonic events during the ultrasound propagation. On the basis of ultrasonic scattering and absorption, the continuous ultrasonic waves are represented as discrete and independent phonons. By recording the scattering events, tracing the trajectory of a moving phonon and calculating the number of phonons that finally reach the receiving transducer, the ultrasonic attenuation coefficient is obtained to be a frequence-dependent spectrum. Numerical investigations have been carried out to predict and compare the ultrasonic attenuation for a solid-liquid two-phase system with a single type particle. After verifying its feasibility, such a method is then applied into mixing particle system, where the mixing iron particles and glass beads with various ratios are set as examples for the purpose of predicting ultrasonic attenuation for the monodisperse and polydisperse mixing particle systems. The results of MCM, the ECAH model, the Lloyd & Berry (LB) model and the Waterman model match well when the particle volume concentration is lower than 10%, corresponding to iron particles and glass beads respectively. In the case of two-phase system with mixing particles, it is shown that as the particle volume concentration increases to 10%, the variation of the ultrasonic attenuation coefficient with mixing ratio yields a nonlinear tendency. The physical properties of particles can also influence ultrasonic attenuation significantly.