基于蒙特卡罗原理的混合颗粒三相体系声衰减计算模型研究  

Ultrasonic attenuation model of mixed particle three-phase system based on Monte Carlo method

作　　者：赵宁宁 肖新宇 凡凤仙[1] 苏明旭[1] Zhao Ning-Ning;Xiao Xin-Yu;Fan Feng-Xian;Su Ming-Xu(School of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093

出　　处：《物理学报》2022年第7期211-218,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51776129)资助的课题。

摘　　要：从单个固体和液滴颗粒的声吸收和散射特性计算入手,基于概率统计的蒙特卡罗方法(MCM),将声波以离散化的声子加以处理,通过追踪其运动历程并进行事件统计,建立一种气体介质中球形混合颗粒的声衰减预测模型.对空气中铝粉颗粒和亚微米级水滴的声衰减分别计算和验证后,将模型推广至含有混合颗粒的三相体系,对铝粉和液滴构成的单、多分散混合颗粒体系进行数值研究.结果表明:两类颗粒的声吸收特性差异明显,其散射声压均随颗粒无因次尺寸kR的增加呈现从后向散射占主要地位逐渐过渡到前向增强的趋势.气液固混合颗粒三相体系中,颗粒类型对于声衰减影响明显、且随浓度的增加不同颗粒的衰减贡献不再遵循随混合比的线性递变关系;对于多分散体系而言,声衰减谱受平均粒径影响较大,对于粒径分布宽度参数则不敏感.模型可进一步结合数学反演形成混合颗粒体系测量的理论基础.From the perspective of calculating ultrasonic absorption and scattering properties of individual solid particle and droplet,the ultrasonic wave is treated as discrete phonons.And by tracking their motion process and event statistics,a new prediction model of ultrasonic attenuation of spherical mixed particles in gaseous medium is established with Monte Carlo method.Considering the difference in physical properties between solid particles and liquid particles,the ultrasonic absorption characteristics of the two kinds of particles are obviously different,and when dimensionless particle size kR≤1,the backs cat ter ing of particles is uniform and dominant,then the ultrasonic scattering pressures gradually transit from the dominant position of backs cat ter ing to the trend of forward enhancement with the increase of dimensionless particle size.The numerical simulation results for the system with a single particle type are compared with those from various standard models such as classical ECAH model and McC model,showing that they are in good agreement.Similarly,the results are then compared with experimental results,which accord with each other in general.After calculating and verifying the ultrasonic attenuation of aluminum particles and submicron droplets respectively in air,the method is extended to the three-phase monodisperse and polydisperse mixed particle system composed of aluminum particles and liquid droplets.In the three-phase system of gas-liquid-solid mixed particles,the particle type has a significant influence on ultrasonic attenuation,and the attenuation contribution of different particles against mixing ratio does not follow the linear gradient with the increase of volume concentration.For a polydisperse system,the ultrasonic attenuation spectrum is greatly affected by the average particle size,but it is insensitive to the width of particle size distribution.The numerical results also show that both the particle type and particle distribution size should be carefully take into account in the polyd

关 键 词：蒙特卡罗法 混合颗粒三相体系 多分散 声衰减 

分 类 号：O359[理学—流体力学]