Inertial Focusing Characteristics Of Particles In Zigzag Channel

High-throughput focusing and particle separation are very attractive for biomedical applications.And microfluidic chips based on the inertial effect has the advantages of low sample injection volume,fast flow speed,and easy portability,which is very suitable for real-time disease detection technology in biomedicine.In recent years,microfluidic chips which using symmetrically curved microchannel structures for inertial focusing and separation,has aroused great interest due to its parallel linear structure,small device footprint,superior particle focusing performance,and easy particle separation.However,the directions of curvature of these microchannels are alternating,resulting in changes in the intensity and direction of the corresponding secondary flow.The accumulation of such changes along the channel will lead to unpredictable inertial migration behavior of the particles.Aiming at this phenomenon,this paper adopted the method of numerical simulation to simulate the flow field change and its interaction with micro-sized particles.The inertial focusing characteristics of particles in zigzag channels under different conditions were studied.First,the migration behavior of different size particles was calculated by varying flow velocity.The results showed that when the flow velocity is low,the inertial lift and Dean drag force can balance the particles to both sides of the channel.When the flow velocity is increased,the Dean flow that continuously changes direction in the cross section of the channel plays a major role in the flow field and can focus the particles on the center of the channel.Compared with small particles,the focusing position of large particles is more biased towards the center of the channel and the focusing effect is better.Then,the migration behavior of particles in channels with different geometric was calculated.The results showed that the 60° zigzag angle can reach the minimum channel pressure drop without affecting the particle focusing state.The channel aspect ratio of 0.5 is the zigzag channel structure that can be used for the best particle focusing and sorting effect.The calculation results were integrated and drawn into a particle focus pattern distribution map.Finally,the serpentine,square wave and zigzag channel were used as the computing environment to study the differences in the migration characteristics of particles in the inertial flow field of similar structure channels.The results showed that when the flow velocity is high,the zigzag channel has the best focusing effect,and has proved to have good particle separation potential.It can separate 5 ?m and 10 ?m particles at Re C = 62.5 with 10 ?mdistance.Therefore,this article has a guiding significance for the selection and optimization of symmetric curved channels.