Numerical Study Of Underwater Acoustic Streaming And Analysis Of Suspended Particle Motion In Standing Wave Acoustic Streaming

With the rapid development of MEMS.Microfluidic driving technology is widely used in biochip,fuel transport and integrated circuit.The microfluidic driving utilizing the non-linear effect of ultrasound has the advantages of simple structure and high efficiency,so it has a good development prospect.In this paper,2-D unsteady and viscous weak compressible equations are solved by computational aeroacoustics.One-step method is used to solve the sound motion and unsteady flow,and the effect of acoustic streaming is directly analyzed.The following studies have been carried out:1.Verify the accuracy of the numerical method.It is proved that the method used in this paper can be used to solve the problem of viscosity and solid wall effect in water.The diffraction and interference phenomena of sound waves are simulated,it is proved that the numerical method can simulate the propagation characteristics of sound wave.2.The acoustic streaming near the solid wall is studied when the sound wave passes through the wall horizontally.Due to the reciprocating vibration of the fluid medium in the sound field,the acoustic streaming is formed by the friction between the fluid and the solid wall,especially the reverse acoustic streaming appears near the wall.The influence of Reynolds number on the wall effect is also analyzed.3.A structure of multistage sound source driving fluid is designed and numerically studied.The relationship between the sound wave length,intensity,series and the driving efficiency of the multi-stage sound source driving structure is analyzed.The influence of the shape of the triangular blunt body in the pipeline on the acoustic flow efficiency is also analyzed.4.The motion of suspended particles in the standing wave acoustic streaming field was numerically analyzed using the two-step method.Firstly,the standing wave acoustic streaming is validated.It is proved that the calculation model can successfully simulate the two-dimensional standing wave acoustic streaming.The critical radius of particles with the same acoustic radiation force and viscous force is obtained by theoretical calculation.Finally,the trajectory of suspended particles is calculated under different particle radius conditions.This study has theoretical value for ultrasonic driving of microfluids.Through this study,it is found that the multistage sound source driving mode has good fluid driving efficiency and feasibility.Follow-up research can carry out relevant experimental verification on this basis,which has guiding significance for the next study of high-efficiency microfluidic device.