Acoustic Radiation Force Of Spherical Particles In A Liquid-filled Cylindrical Tube Under The Action Of Sound Waves

With the development of science and technology,the demand of manipulation technology with precision and high-resolution in production and life is increasing.It is necessary to achieve the precise manipulation of microparticles in different fields and environments.In some actual environments,the size of the particles manipulated ranges from micrometers and nanometers,and the strength of the particles is relatively weak.In these cases,the macro mechanical manipulation is difficult to accord with the actual needs.Therefore,the research of micromanipulation technology become more and more important.In the process of manipulation,the manipulation can be divided into contact manipulation and non-contact manipulation according to whether the control device contacts the target particles.Through the interactions between the field and the targets,non-contact manipulation does not need to touch the controlled particles and can avoid the damage and pollution,which has extensive application in life science,material chemistry fields,chemical engineering.On the basis of different physical fields,the technology mainly includes optical control,electromagnetic control and acoustic control and so on.Acoustic manipulation technology is utilized to trap and move single or multiple particles because of the exchanges of energy and momentum between acoustic waves and target particles.The core of acoustic manipulation technology is the acoustic radiation force which is the mechanical characteristics of the interaction between the acoustic wave and the target particles.To achieve the refinement and predictability of acoustic manipulation technology,the research on the acoustic radiation force of particles in the sound field has great significance.Usually,the actual manipulation occurs in a bounded space,and the acoustic radiation force characteristics of particles are affected by many factors,such as incident acoustic wave,particle structure,material boundary,and fluid medium.Exploring the influence of different environmental parameters on acoustic radiation force of the particle becomes the key to the research and development of acoustic manipulation technology.In the actual operating environment,the cylindrical tube filled with water is a common boundary.So the study of the acoustic radiation force of spherical particles in the cylindrical tube is helpful to promote the development of acoustic manipulation technology in biomedical field or microfluidic device design.In this paper,according to the objective environment of acoustic manipulation system in an actual cylindrical tube,the factors influencing acoustic radiation force of a spherical particle in a fluid-filled cylindrical tube are studies,and some qualitative laws of particle acoustic manipulation in tube are obtained.The main contents and innovations are as follows:1.At first,the acoustic scattering models of sphere with different material(rigid,fluid and elastic)in free space are obtained on the acoustic wave theory.Based on the sound scattering theory,the acoustic radiation force on a spherical particle in free space with incident plane wave is showed by integrating the radiation stress tensor of the spherical surface.The finite element method is used to calculate the acoustic radiation force and the specific steps is introduced.2.The acoustic scattering models of a plane wave incident on a sphere in a cylindrical tube filled with ideal fluid is established.Combined with different particles such as elastic sphere,elastic double-layered sphere,and multi-layered capsule that may exist in the actual control environment,the expressions of sound scattering coefficients under these different conditions in the tube are derived.The analytical expression of the acoustic radiation force on the spherical particle is deduced by integrating the acoustic radiation stress tensor of the spherical surface.The influences of the tube wall and the spheres with different materials and structures on the acoustic radiation force of the spherical particle is analyzed.Considering the difference of pipe wall in actual control environment,the acoustic radiation forces in rigid pipe and impedance are calculated,respectively.The theoretical results are verified by utilized finite element methods.The results show that the maximum or the minimum values of the acoustic radiation force on the sphere in the tube appear,and the frequency corresponds to the resonance of the cylinder cavity filled with the ideal fluid.The different materials and structures of the sphere affect the magnitude and direction of the acoustic radiation force.And the shell material of the sphere with multilayer structure has a great impact on the acoustic radiation force,which means that the material characteristics cannot be ignored in the acoustic manipulation experiment.When the sphere has three layers,the response of the acoustic radiation force to the radius changes the spherical core is not obvious,in other words,when the three-layered sphere is manipulated the radius size of the core drug can be selected flexibly.In addition,at the resonance frequencies the acoustic radiation force on the sphere in an impedance tube is smaller than that in a rigid tube.3.The geometry of the tube will affect the sound field,and the influence of the different boundaries is different.The acoustic scattering model of a sphere in the tube with suddenly changed cross-section in incident plane wave flied is established.The acoustic radiation force on the sphere is derived.The influences of the position of the sphere in the tube and the suddenly change of the cross-section on the acoustic radiation force of the sphere are investigated.The numerical calculation is carried out by using the finite element method to verify the theoretical results.Simulation results shows that the influences of the distance from the sphere in the tube to the location that the shape of the tube changes on the acoustic radiation force is periodic sinusoidal.With the change of the ratio of the front radius to the back radius at the suddenly changed of cross-section,the direction of the acoustic radiation force changes will change.4.Based on the acoustic scattering theory and the finite element method,the analytical theory and numerical model of the acoustic radiation force of spherical particles in the tube connected with a Helmholtz resonator end are established.The position of spherical particles in the tube and the influence of the parameters of the Helmholtz resonator on the acoustic radiation force of the sphere are analyzed.The results show that the acoustic radiation force on a spherical particle in the tube varies periodically with the distance from the core of the sphere to the Helmholtz resonator.The change of the linear parameters of the Helmholtz resonator will affect the magnitude and direction of the acoustic radiation force on the spherical particles.The changed law of the acoustic radiation force is affected by the changes of the resonant frequency of Helmholtz resonator.According to the influence of different boundaries on particle manipulation,the experimental device of acoustic manipulation should be designed in the actual manipulation environment.5.When the incident sound wave propagates in the tube and the excitation frequency of the sound source is higher than the normal frequency fmv of the tube,there is the incident wave of(m,v)normal-mode acting on the spherical particle in the tube.In this paper,under the superposition of incident wave of(m,v)normal-mode,the acoustic scattering model of the spherical particle in a circular waveguide tube is established.The analytical expression of the acoustic radiation force on the sphere is derived.The analytical results are verified by the finite element method.The analysis shows that,under the single incident wave of normal-mode,at the resonance frequency of fluid-filled tube the valleys of the acoustic radiation force appear when the root m is the same,but the variation law is different when the normal-mode of the incident wave is different.When the incident sound field in the tube is the superposition of(m,v)normal-mode,the peaks and valleys of the acoustic radiation force on the sphere appear at the different resonance frequencies of(m,v)normal-mode.In addition,the amplitude of radiation force is mainly affected by the wave of(0,v)normal-mode.Therefore,when the acoustic manipulation experiment is carried out in the tube,considering the influence of high-order wave propagation can further improve the theoretical model and provide more accurate theoretical guidance for manipulation.In this study,combined with the actual control scene,the analytical and numerical model of acoustic radiation force for an incident sound wave acting on a spherical particle in the tube under different manipulated environment is established.The influence of various factors on the acoustic radiation force of the sphere in the tube is analyzed.The research results will provide a theoretical guidance for the design of acoustic manipulation system and the application of acoustic manipulation technology in practice,and promote the fine development of the acoustic manipulation system in the tube.