Simulation Analysis And Experimental Study Of Sorting Particles With Different Density By Standing Surface Acoustic Wave

The efficient sorting of particles is of great significance in the fields of medical detection,chemistry,diagnostic therapy,drug development and synthesis,etc.Particle sorting based on density is widely used in fields of chemistry and biology,such as white blood cell classification,stem cell separation and specific bacteria separation,etc.Sorting technology based on SAW is widely used because of its low propagation loss,easy manufacturing,good biocompatibility,non-contact manipulation and low reagent consumption.Therefore,based on the surface acoustic wave separation technology and hydraulic separation technology,this paper proposes an experimental study on the multilevel separation of particle with different densities by using self-made SSAW separation chip,and explores the influence of the main flow velocity,fluid density,loading signal voltage,outlet flow ratio and other factors on particle separation.The specific research contents are as follows:The acoustic flow effect,the principle of surface acoustic wave generation by the interdigital transducer,and the working principle of the surface acoustic wave device are analyzed and introduced.The properties of the fluid in the microchannel of the separation chip are discussed.Finally,the force of particles in the SSAW field is analyzed,which lay a theoretical foundation for simulation analysis and experiments.Determine the materials of the piezoelectric substrate,the interdigital transducer and the microfluidic system.Design the interdigital transducer and the microfluidic system.After that,we use MEMS?Micro-Electro-Mechanical System?technology to manufacture the bottom film and acoustic surface wave device,use the molding method to manufacture PDMS micro-channel system,and then use natural bonding method to bond surface acoustic wave device and the micro-channel system.Finally,sorting chip for experiment is obtained through subsequent treatment such as connection of pipelines and wires.The multi-physics simulation software COMSOL is used for modal analysis and harmonious response analysis of the surface acoustic wave device to determine the working frequency of the surface acoustic wave device.Then,MATLAB software is used to simulate and analyze the motion track of three different density particles in the SSAW field,and to explore the influence of different input voltage and main flow velocity on the motion track of particles with different densities.Finally,the optimal parameters are loaded on a three-dimensional simulation model,and COMSOL software is used to explore the influence of different outlet flow ratio on particle trajectory,so as to determine the better particle separation parameters.Design the experimental scheme and build the experimental platform.Using the self-made sorting chip to carry out experimental research,to explore the influence of loading voltage,main flow velocity,fluid density,outlet flow ratio and other factors on particle sorting effect and determine the best sorting parameters and determine the best sorting parameters.The experimental results show that the two types of sorting chips can sort three kinds of particles:polymethylmethacrylate?PMMA?microspheres,silica microspheres,and polystyrene?PS?microspheres with diameters of 10?m.The best sorting parameters for direct sorting chip are:v_max=5mm/s,V_pp=15V,B₁=0.2,B₂=0.6,and the best sorting parameters for sequential sorting chip are:v_max=5mm/s,V_pp=15V,A₁=0.2,A₂=0.25.And the sorting effect of sequential sorting chip is better than direct sorting chip.