Numerical Study Of Micromixer Based On Cantor Fractal

Microfluidic chip is a kind of micro-experimental instrument which combines biological analysis and chemical analysis.It is one of the hot research directions in the society nowadays.As the basic part of microfluidic chip,micromixer also provides important application value in biochemical engineering.At present,micromixers can be divided into two types:passive micromixer and active micromixer.The passive micromixer relies on the complex structure design of the internal microchannel to improve the mixing efficiency.The main difference between passive micro-mixer and active micro-mixer is whether external energy is needed to promote fluid mixing.Combining the theory and research of a large number of researchers,this paper combines the Cantor fractal structure in mathematics with the design of micro-mixer,and designs many passive micro-mixer and electroosmosis micro-mixer with Cantor fractal structure.And the numerical simulation is carried out.Finally,the fabrication of the micro-mixer is also investigated experimentally.The main contents of this paper are as follows:?1?Fractal geometry structure is designed based on Cantor fractal principle,and fractal structure is combined with microchannel design to construct micro-channel with fractal structure.By means of simulation and comparison,the parameters are optimized,and the fractal structure can effectively break the laminar flow,increase the mixing path and promote the mixing of the fluid,so as to promote the mixing and convection,and finally,a high-efficiency simulated Cantor fractal micro-mixer is designed.?2?The fractal structure based on Cantor fractal principle is applied to the wall design of micro-channel to form fractal groove or fractal plate.Through the simulation comparison of various micro-channels,it is concluded that the SFO structure is superior to the PFO and TFO structures.It can obviously cause the mixing trend of fluid,so the high efficiency SFO micro-mixer with Cantor fractal plate concave groove is designed.?3?The electroosmotic micromixer is designed based on Cantor fractal.Through the preliminary study,the main parameters compared are electrode length,fractal electrode spacing,the voltage applied on the electrode,frequency and other factors.And the final conclusion is that under the same voltage and frequency,the electric field generated by the Cantor fractal electrode with200?m spacing can promote the strong chaotic vortex of the fluid.Finally,the electroosmotic micromixer with the Cantor fractal structure is designed to improve the mixing efficiency by 50%compared with the one without the electrode.?4?In this article,the micro-channel processing of PMMA,PET,PS and other microchannels is carried out on the basis of the existing laboratory.By changing the power and radius of laser cutting,the micro-channels can be affected differently.To explore the hot bonding parameters of hot-pressing chip bonding machine for different material chips.Finally,the Cantor fractal micromixer chip of double-layer PS material and the Cantor fractal micromixer chip of four-layer PMMA material were successfully fabricated by means of CO₂ laser processing and hot-pressing bonding.The sample mixing experiments were carried out to verify the results.In general,by introducing the Cantor fractal into the design of the micro-channel,it is found that the Cantor fractal structure can effectively promote the generation of mixed convection,and the active and passive micro-mixer with better mixing effect is designed by numerical simulation and simulation.The design and development of the micromixer have certain guiding value.