Optimization Design And Simulation Experiment Study Of Passive Micromixer

Microfluidic technology simplify traditional biochemical detection processes such as preparation of sample,mixing,and the chip detection.It has been widely used in the fields of medicine,biology,analytical chemistry and environmental monitoring.Micromixer is an important part of microfluidic chip,it can significantly shorten the pretreatment time of sample and greatly improve the detection efficiency of microfluidic chip.According to the working principle of the micromixer and whether it is necessary to add external energy sourse to promote fluid mixing,the micromixer can be divided into a passive micromixer and an active micromixer.Most of the active micromixers are complex to manufacture and difficult to integrate with other systems,which is not conducive to mass production.The method to improve the mixing efficiency of passive micromixer is mainly through changing its internal structure.Because of its simple structure,it is conducive to manufacturing,so it is widely used in microfluidic technology.In this paper,two types of micromixers are designed according to the mixing mechanism,the first one is a rhombus micromixer.It use the principle of converging and diverging to promote the chaotic convection phenomenon of the fluid and improve the mixing efficiency.The second micromixer is an innovative application of Murray's law,which is followed by mammalian circulatory systems.The tree-like fractals designed according the murray's law are used as obstacles to place in the T-microchannel,the micromixer with this structure can have high mixing efficiency.The mixing performance of the micromixer is comprehensively analyzed from three aspects,including pressure drop,mixing efficiency and fluid flow in the micro channels.For rhombic micromixers,the optimal structure is obtained by changing the width ratios,rhombic angles and the combination of different geometric units.The results show that the smaller width ratios and the smaller rhomboid angles can lead to the large area of chaotic convection in the microchannel and improve the mixing efficiency.For the obstacle micromixers,we study the effect of the branch angles,the number of levels,asymmetric structure and the distance of the obstacles on the mixing efficiency of the micromixer.The rhombic micromixer designed in this paper and the onstacle micromixers based on the Murray's law have a good mixing performance,which provides a new idea for the design of passive micromixers.