超声台上水滴中声学流的研究

发布时间：2018-01-29 03:13

本文关键词： 有限元仿真声学流超声台微纳物体水滴　出处：《南京航空航天大学》2014年硕士论文　论文类型：学位论文

【摘要】：压电作动器的应用十分广泛,可实现对微纳物体的吸附、聚集、移动、旋转等操纵。在生物医学等领域具有重要研究价值。本文使用COMSOL Multiphysics软件对一种用于银纳米线径向点聚集的超声台进行了有限元模型分析,研究超声台上水滴中声学流的产生机理及其影响因素。主要内容如下:实现了超声台上银纳米线径向聚集实验,得到了银纳米线径向移动速度与超声台中心点o振动速度之间的特性曲线。利用COMSOL软件在声—压电耦合物理场中建立了超声台的有限元模型,并对有限元模型进行了模态分析和谐响应分析。利用声—压电耦合场求解出水滴内部振动速度和声压分布后,在蠕动流物理场中求解出水滴中声学流的流动分布,并仿真计算得到声学流流速与超声台中心点o振动速度的特性曲线。与实验数据的吻合证实了模型与求解方法的正确性。研究影响声学流在水滴中分布的因素,发现雷诺应力的梯度对声学流的流动分布起到主导作用。同时,研究了声学流与超声台各组分尺寸间的关系特性,得出了声学流流速与分布随相关因素变化的一般规律。硅基板的厚度减小可增大声学流流速,压电圆环的厚度增加可增大声学流流速;对于固定的压电圆环内径或外径,存在相应的外径值或内径值,使声学流流速最大;在硅基板上开槽可增大声学流流速。
[Abstract]:Piezoelectric actuators are widely used to achieve the adsorption, aggregation and movement of micro and nano objects. Rotating equal manipulation. Has important research value in biomedical and other fields. This paper uses COMSOL. The finite element model analysis of an ultrasonic platform used for radial point aggregation of silver nanowires was carried out by Multiphysics software. The mechanism and influencing factors of acoustic flow in water droplets on ultrasonic platform were studied. The main contents were as follows: the radial aggregation experiment of silver nanowires on ultrasonic platform was carried out. The characteristic curves between the radial moving velocity of silver nanowires and the o vibration velocity at the center of the ultrasonic station are obtained. The finite element model of the ultrasonic station is established by using COMSOL software in the acousto-piezoelectric coupling physical field. The modal analysis of the finite element model is carried out and the acoustic and piezoelectric coupling field is used to solve the vibration velocity and pressure distribution of the water droplet. The flow distribution of acoustic flow in water droplets is solved in the physical field of peristaltic flow. The characteristic curves of the velocity of acoustic flow and the velocity of vibration at the center of ultrasonic station are obtained by simulation. The validity of the model and the solution method is confirmed by the agreement with the experimental data. The factors influencing the distribution of acoustic flow in water droplets are studied. It is found that the Reynolds stress gradient plays a leading role in the distribution of acoustic flow. At the same time, the relationship between the acoustic flow and the size of each component of the ultrasonic station is studied. The general law of the velocity and distribution of acoustic flow is obtained. The thickness of silicon substrate can increase the velocity of acoustic flow, and the thickness of piezoelectric ring can increase the velocity of acoustic flow. For a fixed piezoelectric ring with internal or external diameter, there are corresponding external diameter or internal diameter, which makes the acoustic flow velocity maximum. The slotted silicon substrate can increase the acoustic flow velocity.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB552

【共引文献】