The Research On 3D Spiral Microchannel Separation Technology

In In medical diagnosis and drug screening,particle separation and improvement of particle concentration are crucial.Precise control of microfluidics inertia effect can be achieved with high particle flux,such as plasma purification,particle separation,extraction of circulating tumor cells,cell concentration,pathogen detection and so on.Due to the limitation of traditional soft lithography processing methods,most of the widely used micro-channel separation devices are 2D plane structures.According to the stress characteristics of particles in the micro-channel,the UDF module of Fluent was used to develop the inertial lift calculation program,and the 2D single-spiral micro-channel numerical analysis model was established,which was compared with the particle motion data measured by binary and multivariate media experiments.On this basis,the key parameters that affect the particle separation performance in 2D single-spiral micro-channel,such as particle relative size K,Reynolds number Re and channel curvature ratio,are studied.The results show that the numerical model calculated in this paper is in good agreement with the experimental trend,and the accuracy of the numerical model is verified.At low Reynolds number(Re=4.45),particle focusing is easier when the relative size of particle is greater than 0.07.At a medium Reynolds number(Re<270),the particle size was about 0.22.With the increase of Reynolds number,the stable position of the particle gradually approached the inner wall from near the center of the channel.However,when the particle size is small(about 0.1),with the increase of Reynolds number,the stable position of the particle tends to approach the inner wall first and then the outer wall gradually.To solve the problem of unstable particle separation caused by the curvature change of 2D micro-channel,a 3D spiral micro-channel is designed by using the latest flexible micro-channel technology.The focusing process of 10 m and 25 m particles at different flow rates was obtained by numerical analysis.Finally,the separation performance of particles was verified by the experimental platform.The results show that the 9 rings 3D hose microchannel designed in this paper can achieve high throughput and high efficiency separation of 10 m and 25 m particles.With the increase of Reynolds number,the stable position of 10 m particles(relative size of particles 0.1)approached the inner wall from near the center of the channel,and then approached the outer wall when the Reynolds number was greater than 106.The particle with diameter of 25 m(particle relative size of 0.25)approached from the center to the inner wall with the increase of Reynolds number.The separation of 10 m and 25 m particles was best when the Reynolds number was 106.