用蒙特卡罗方法预测液固两相体系中颗粒的超声衰减

Prediction of Ultrasonic Attenuation in Liquid-Solid Particulate Two-phase System with Monte Carlo Method

为研究高浓度颗粒两相流中超声复散射现象并建立颗粒表征模型,从单颗粒弹性散射理论出发,采用蒙特卡罗方法预测不同粒度、浓度及超声频率下玻璃微珠/水颗粒两相体系中颗粒的超声衰减特性.在颗粒体积浓度低于1%时,蒙特卡罗方法与基于单散射理论的ECAH模型吻合较好,随颗粒体积浓度和颗粒尺寸增加,声的衰减呈非线性变化,二者差异增加.利用该方法预测颗粒半径为35和90μm的液固两相体系随浓度衰减变化的结果与文献实验值基本一致.蒙特卡罗方法可用于50%固相体积浓度范围内超声衰减计算并为超声法颗粒测量提供理论模型基础.

For the study of complex sound scattering phenomena, the Monte Carlo method was investigated to establish a novel particle size characterization model in concentrated particulate two-phase flow. Starting from the single particle scattering theory, the numerical simulation was carried out to predict the acoustic attenuation characteristics in the two-phase system of glass bead/water with different particle sizes, concentrations and ultrasonic frequencies. Through the comparison of ECAH model of single scattering theory, it was found that they met each other well at the concentration of 1%（~o）, while clear divergence occurred with the increase of the concentration. At the same time, the simulation results were compared with experiment result from literature. It was shown that the attenuation in the particle radii of 35 and 90 ~tm in two-phase system predicted by Monte Carlo method agreed well with experiments. The proposed Monte Carlo method could be used for calculating the attenuation in high particle volume concentration of 50% and numerical modeling of particle size measurement in the complex scattering condition.