The Numerical Simulation Research Of The Irregular Particle Manipulation In Microfluidic Chip

The Microfluidic chip can manipulate and analyze the fine paticles suspended inthe fluid. When the characteristic scale of the device has fallen into micro scale, it canimprove the resolution and reliability of the particle control. Particle control hasachieved great success in the study of homogeneous spherical particles, especially in thedifferences research about individual paticles,which are based on the single particlecontrol. However, natural or man-made heterogeneity, nonspherical micro particles aremore widespread, such as red blood cells, Janus particles, carbon nanotubes, dumbbellshape particles system and so on.The specificity of their shape, material compositionand connection will make it more difficult to control. Studying the motion of thesecomplex particles in microfluidic chip and the mechanical response in the appliedphysical fields (electromagnetic field and temperature field, etc.) is the foundation ofimproving control ability.Existing conventional numerical CFD or more physical simulation platform aremostly based on Euler-Lagrange method,which introduces particle phase after the flowfield simulation. The mechanical model of particle phase is mostly base on thehomogeneous spherical particles, then do some correction. The accuracy of this methodcan be accepted in the transport study of a large number of particles, but is unable toobtain satisfactory results for single particle manipulation which mainly depends onparticle itself.In view of this, this paper takes Comsol Multiphysics simulation platform, and thenumerical simulation method for the irregular surface characteristics particles andirregular shape particles is established:For the irregular surface characteristics particles,Janus particles, this paper establishs the particle dynamics model by analyzing the motion process of Janusmicrospheres.This paper studys the motion characteristics of two kinds of Janusmicrospheres particle size （1μm、2μm）under the self-propolled force by means ofnumerical simulation, and obtains the different motion patterns, mean squaredisplacement and Hurst index. Numerical simulation results are in good agreement withcorresponding experimental results. On the one hand, this study may help to deepen thecurrently understanding in Janus particle movement, on the other hand, it can establisheffective means of research for subsequent manipulation and application and lay a solidfoundation for the control and application of Janus particles;For the irregular shape of micro particles, a single complex particle discrete for anumber of different spherical particle in this paper, and then to construct the targetparticle model through the interactions of different link between spherical particles. Thispaper uses this method to roughly simulate the kinetic characteristic of "particle-DNA-particle" in the sudden expansion-sudden contraction variable cross-sectionmicro-channel, and to simulate the state of motion of Janus particle under the control ofpulse type dielectrophoresis. The two phenomena are consistent with the experimentalresults, which shows that this method can get the characteristics of motion of particlesunder the action of multi-physics field(flow field, electric field, Brownian movement,etc.), and may provide a fast and reliable means to to design irregular particle controldevice in microfluidic chip for its simple calculation and high efficiency.