共聚焦超声换能器的声场优化与粒子捕获  

Sound field optimization and particle trapping of confocal ultrasonic transducer

作　　者：狄苗 何湘 刘明智 闫善善 魏龙龙 田野 尹冠军[1,2] 郭建中[1] Di Miao;He Xiang;Liu Ming-Zhi;Yan Shan-Shan;Wei Long-Long;Tian Ye;Yin Guan-Jun;Guo Jian-Zhong(School of Physics and Information Technology,Shaanxi Normal University,Xi’an 710119,China;Key Laboratory of Modern Teaching Technology of Ministry of Education,Shaanxi Normal University,Xi’an 710062,China)

机构地区：[1]陕西师范大学物理学与信息技术学院,西安710119 [2]陕西师范大学现代教学技术教育部重点实验室,西安710062

出　　处：《物理学报》2023年第1期196-201,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12004237,11727813,12034005,11904221);中国博士后创新人才支持计划(批准号:BX20190193);中国博士后科学基金资助项目(批准号:2020M683416,2019M663612);陕西省科学技术协会青年人才托举计划项目(批准号:20220523)资助的课题。

摘　　要：超声悬浮被广泛应用于多个领域,目前主要有驻波式和相控阵式悬浮系统.基于共焦点排列的聚焦换能器结构,本研究提出了一种单边式超声悬浮系统.其基本原理是利用反相激励成对聚焦换能器在空间构建具有势阱结构的特定声场,实现微粒的捕获与悬浮.针对4个共焦点排列的聚焦换能器,基于有限元仿真研究了换能器轴夹角及激励相位模式对声场分布的影响;利用实验演示了系统的粒子捕获效果,验证了其势阱分布情况.结果表明,换能器轴线与结构中轴线夹角为45°时,势阱强度最高;换能器的激励相位分别为0,0,π,π时,声场中存在1处主势阱、2处次级势阱,可以捕获3处粒子团;换能器的激励相位分别为0,π/2,π,3π/2时,声场中仅存在1处势阱,只可捕获1处粒子团.该系统具有成本低、自由度高、稳定性强、操作便捷的优点,且能够实现单个位置或多个位置粒子团的捕获与悬浮,可以用于流体中高密度物体操控.The nonlinear effect of high-intensity sound waves produces the acoustic radiation force(ARF),which are used for acoustic levitation and manipulation practical.With no special requirement for the physical and chemical properties of the controlled objects,acoustic levitation owns a promising application prospect.The common levitation scheme includes the standing-wave system and phased-array levitation system.The standing-wave system has poor performance in the aspects of the degree of spatial freedom,the ARF along the non-axial direction,and the levitation stability.The phased-array system requires a complex control system and a high production cost.Here,we propose a single-side acoustic levitation system based on the paired confocal focused transducers.By driving the transducer pairs with reverse phase mode,two anti-phase focused spherical waves interfere with each other,resulting in constant sound pressure of 0 Pa at the focus.The resulting potential well can achieve stable particle capturing and levitating.First,we verifed the theoretical feasibility of the system according to Huygens’ principle.Then,using the finite element method,we analyzed the influences of structural and driving parameters on the sound field distribution,such as the angle between the transducer axis and the central axis of the structure and the excitation phase modes.Finally,we demonstrated the particle trappings under two kinds of excitation phase modes of the levitation system experimentally.The results show that,1) the intensity of the dominating potential well reaches a strongest value when the structural angle is 45°;2) as the excitation phases are 0,0,π,and π,the sound field owns three potential wells which can capture three clusters of quartz sands,the primary potential well is stronger than the secondary one;3) as the excitation phases are 0,π/2,π,and 3π/2,the sound field owns one potential well and captures one cluster of quartz sands.The isosurface of wave intensity around the potential well is more comprehensive than in

关 键 词：超声悬浮 声场势阱 聚焦换能器 粒子捕获 

分 类 号：TB552[理学—物理]