超声驻波声悬浮能力及其稳定性仿真与实验

发布时间：2018-03-26 05:52

本文选题：超声驻波悬浮　切入点：声悬浮力　出处：《哈尔滨工业大学》2014年硕士论文

【摘要】：超声驻波悬浮技术，是非接触式支撑技术的一种，它能够用来模拟空间环境的微重力、无接触等特性，为生物化学以及材料科学领域提供一种接近理想状态的实验条件，还能够克服传统的接触式操作对精密零件表面的破坏等问题。超声驻波悬浮是利用超声换能器的辐射端产生高频的活塞式振动，在介质中形成声场，在声波传输路径上放置反射端，使声波反射回来与入射声波相互叠加，调节辐射端面与反射端面之间的距离，使之为超声波半波长的整数倍，入射波与反射波在声场空间中反复多次叠加形成高强驻波声场，并形成辐射声压，置于驻波声场中的物体在辐射声压的作用下，将达到悬浮状态。本文首先分析了理想媒质中的声波方程，，并通过平面驻波的基本概念，推导出了平面驻波声场中，媒质质点速度及声场空间中声压的分布；结合Gor’kov的时间平均势理论，推导出相对时间平均势、轴向声悬浮力和声回复力常数的表达式，并理论分析了被悬浮物在驻波声场中稳定悬浮的位置；通过建立简化的碰撞模型，从动量交换的角度，分析了驻波声悬浮的基本原理并定性分析悬浮位置。其次，探讨了具有平面反射面的声悬浮系统的结构参数（谐振腔长度、反射端面直径和辐射端面直径）对悬浮能力的影响，确定了反射面为平面时最优结构尺寸参数。根据凹球面的聚焦作用，将反射面设计为凹球面的形式，优化了声悬浮装置的结构参数；对超声驻波声场进行了仿真，分别确定了反射面为平面和凹球面时，在不同谐振腔长度下，声场中的理论悬浮位置及每层悬浮位置处的轴向和径向回复力常数，对比悬浮系统的悬浮稳定性。最后，根据单轴式声悬浮的原理，建立了简易的声悬浮实验装置。对直径为2mm的泡沫球进行了平面/凹球形反射面悬浮能力、悬浮稳定性实验，实验验证声悬浮装置的悬浮能力及其稳定性。
[Abstract]:Ultrasonic standing wave suspension is a kind of non-contact support technology. It can be used to simulate the microgravity, non-contact and other characteristics of space environment, and to provide a near ideal experimental condition for the field of biochemistry and material science. The ultrasonic standing wave levitation is a kind of high frequency piston vibration produced by the radiating end of the ultrasonic transducer and forms sound field in the medium. The reflection end is placed on the path of acoustic wave transmission, so that the reflection of sound wave is superimposed with the incident sound wave, and the distance between the radiation end surface and the reflection end surface is adjusted to make it an integral multiple of the half wave length of the ultrasonic wave. The incident wave and the reflected wave are superimposed repeatedly in the sound field to form the high strength standing wave sound field and the radiation sound pressure is formed. The object placed in the standing wave sound field will be suspended under the action of the radiation sound pressure. In this paper, the acoustic wave equation in ideal medium is analyzed, and by the basic concept of plane standing wave, the distribution of the velocity of medium particle and the sound pressure in the space of sound field in the plane standing wave sound field are deduced, and the time average potential theory of Gor'kov is used. The expressions of relative time average potential, axial acoustic levitation force and acoustic recovery force constant are derived, and the position of suspended object in standing wave sound field is theoretically analyzed. The basic principle of standing wave acoustic levitation is analyzed and the suspension position is qualitatively analyzed. Secondly, the influence of structural parameters (cavity length, reflecting end diameter and radiation end diameter) on the suspension capability of acoustic suspension system with plane reflector is discussed. According to the focusing effect of the concave sphere, the reflection surface is designed as the concave spherical surface, and the structural parameters of the acoustic suspension device are optimized, and the ultrasonic standing wave sound field is simulated. When the reflector is plane and concave sphere, the theoretical levitation position in the acoustic field and the axial and radial recoil force constants at each levitation position in different cavity lengths are determined respectively, and the suspension stability of the suspension system is compared. Finally, according to the principle of uniaxial acoustic levitation, a simple experimental device of acoustic levitation is established. The levitation ability and suspension stability of foam ball with diameter of 2mm are tested on the plane / concave spherical reflector. The suspension capability and stability of the acoustic suspension device are verified by experiments.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB552;TB559

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