Study Of Acoustic Radiation Force On Spherical Particles

With the development of modern science and technology, the demands for non-contact control of micro or nano-size particles have been more and more urgent, especially in the biomedical and industrial field. The tiny particles in the sound field can be affected by the acoustic radiation force, the particle can be stabilized at a specific location in the sound field under specified conditions, and by the acoustic radiation force the sound field can operate and capture the particles. Using the interaction between the gradient of sound field and particles, the application of cell manipulation, drug delivery and acoustic levitation can be realized, which will be more important in the research of biomedical and materials science.In this paper, we mainly use two theoretical methods to study the acoustic radiation force on spherical particles by acoustic wave.In the first chapter, we review the theoretical background and application of the acoustic radiation force, introduce the recent researches of the acoustic radiation force, and summarize the main content of the research in this paper.The second chapter mainly introduces the ray acoustics approach. By this method we study the acoustic radiation force on microspheres in the Gaussian field, consider the influence of the sound attenuation in particles on the two-dimension acoustic radiation force, analysis the conditions of production of the potential well, and also discuss the influences the initial position and the size of particle on the acoustic radiation force. Results show that particles can be affected by the sound trap force in a certain position, and the attenuation affects little to the properties of acoustic tweezers.In the third chapter, using the ray acoustics theory, the model of double-layer sphere suffered by radiation force is proposed; the simulations and calculations show the influences of spherical shell’s thickness and medium of the double-layer sphere on the location and size of potential well. We also propose the theoretical model of acoustic radiation force, which is more suitable to experiments and applications.In the fourth chapter, based on the ray acoustics approach, we propose the model of acoustic radiation force on microspheres in the spherically-focused sound field, and analyze the influences of the parameters of the focusing sound field on acoustic radiation force. The results show that the conventional focused sound source also has a three-dimensional capture phenomenon on particle.The fifth chapter describes the acoustic scattering theory, analyzes and discusses the scattering of sound field under various boundary conditions. By the method of finite series expansion, Gaussian focused sound wave is expanded by spherical function. Using scattering theory, we study the acoustic radiation force function of spherical particles induced by Gaussian sound wave, which is important to study the radiation force of complex acoustic waveform.In the sixth chapter, we propose the acoustic radiation force function of Gaussian standing and Gaussian quasi-standing fields by scattering theory, and analyze the characteristics of the suffered acoustic radiation force on spherical particles in Gaussian standing and Gaussian quasi-standing fields. We can illustrate the effect of Gaussian standing field on manipulate particles, which is also consistent with the previous experimental results.In the seventh chapter, we have a summary and prospect of the paper.The paper has systematically studied the characteristics of acoustic radiation force on spherical particles in the sound field, and we deduce several models of various sound fields and conduct research through theoretical analysis, numerical analysis. These works will have important theoretical guidance on acoustic radiation force for nondestructive control in industry and cells or drugs selection in medical science.