Research And Experiment On Particle Manipulation Methods Based On Swirl

Particle manipulation is the key point of the micromanipulation technology and microfluidic chip,which is widely used in many fields,such as bioengineering,MEMS,chemistry,materials science and so on.In recent years,with the miniaturization of manipulation objects,the requirements for micromanipulation technology have become higher.It is of great theoretical significance and application value to study the particle manipulation method based on swirl and to explore the difficult problem of quantification of particle control.In this paper,the mechanism of the swirling flow field formation is studied based on reattaching jet model,and the relationship between the pressure and velocity distribution of the swirling flow field and the flow field parameters is analyzed quantitatively.The quantitative evaluation method of micromanipulation performance base on swirl is proposed,and the effects of the flow field parameters on micromanipulation performance are analyzed.Based on the above theoretical analysis,hydrodynamic model of particle manipulation based on swirl is established.The pressure and velocity distribution characteristics near the stagnation point of the swirl are studied by simulation,and the influence of the flow field parameters on the performance and the micromanipulation performance of the swirling flow field is discussed.Based on the above research,an experimental platform is built to verify the correctness of the theory and the feasibility of the proposed method.The experimental results show that characteristics of the swirling flow field derived from reattaching jet model are related to the flow field parameters;the micromanipulation performance of the swirling field can be described by using the swirl intensity and the radius of the low velocity region.By reasonably matching the flow field parameters and the jet velocity of microtubules to control the position and movement of the stagnation point of the swirling flow field,particles can be trapped,moved and rotated.