Particle Manipulation Method And Its Experimental Study Based On Fluid

The trapping and movement of particles are the key points of the micromanipulation technology,which are widely used in microassembly,disease diagnosis,biomedical engineering,and other fields.The fluid based particle manipulation methods trap and move particles by controlling the flow field.This method does not cause mechanical damage to the particles,and shows its excellent safety and operability.In this paper,the particle trapped and control method base on fluid is studied.The pressure and velocity distribution characteristics of flow field are evaluated theoretically,and the influence of flow field parameters on particle control performance is analyzed by simulation.The correctness of the proposed method is proved by experiments.Firstly,the paper studies the particle trapping and controlling method based on opposed jets: the particle is trapped by the pressure formed on the surface of the particle near the stagnation point of the flow field.The particle can be driven by controlling the movement of the stagnation point of opposed jets flow field;and the clamping direction of the flow field to the particle can be changed by changing the direction of the opposed-jets flow field.Therefore,quantification and directional motion of micron particles of arbitrary shape along any direction are realized.Then a method for controlling the position and attitude of particles based on swirl is proposed: the region near the swirl center is used to trap and control the particles.The particle rotates steadily near the swirl center due to the swirl,and the angular velocity of the particle can be adjusted by changing the intensity of the swirl.By changing the direction of rotation of the swirling field,the direction of particle rotation will also change.The position control of particles is realized by controlling the location of the swirl center.The jet attachment model of swirl flow field is established,and the quantitative relationship between the parameters of microtubules and the shape of swirl flow field is deduced.Based on the above analysis,a simulation model is established to further analyze the velocity and pressure distribution characteristics of the opposed-jets flow field and the swirl flow field.The influence of parameter change on particle control performance is analyzed.The dynamic characteristics of microfluidic controlled particle motion are discussed.Finally,the experimental platform is built and the feasibility of the proposed method is verified by experiments.The simulation and experimental results show that particles can be trapped and controlled by constructing the opposed-jets flow field and the swirling flow field.Particles with an arbitrary size and shape can be trapped and moved directionally and quantitatively with proper flow field parameters.