Study On Mixing Mechanism And Parameter Optimization Of Straight Pipe Electroosmotic Micromixer

With the rapid development of nano materials and MEMS,microfluidic technology has a wide range of applications prospects in biomedicine,chemical analysis and environmental improvement.Among them,electroosmosis is an active scheme to control the flow of micro liquid by applying the external electric field to drive the flow on the wall and form a disturbed eddy current.Electroosmosis drive has become the main development direction of microfluidic control with the advantages of high efficiency,good controllability,low cost,no moving parts and so on.Based on the research of electroosmosis micromixer at home and abroad,this paper studies the mixing mechanism and parameter optimization of straight channel micromixer by using numerical simulation.The main research results and innovations are as follows:Based on the theory of fluid flow in microchannels,the generation mechanism,influencing factors and fluid flow characteristics of electroosmosis are studied,and the physical field control equations and boundary conditions involved in the numerical simulation are analyzed.The two-dimensional straight pipeline electroosmotic micromixer model is established to study the effect of electroosmotic parameters on mixing efficiency.The results show that when the alternating electric field is applied,the chaotic flow at the electrode is induced by electric field electroosmosis to form a vortex,and the fluid is squeezed and stretched.The mixing effect is significantly enhanced compared with that without the alternating electric field;with the increase of the electrode voltage,electrode length and electrode frequency,the average mixing efficiency at the outlet of the microchannel first increases and then decreases,and there is a suitable electrode parameter value to make the mixing efficiency Maximum.The model of three-dimensional cylindrical electroosmosis mixer is established two curved electrodes are placed on the outside of the pipe wall,the influence and mechanism of electroosmosis on the mixing efficiency are analyzed.The results show that the electroosmosis flow field formed by the application of sinusoidal alternating electric field and the flow field of the fluid itself form a composite flow field to work together to mix the fluid.When the electrode length is 10?m,the effect of the circumferential angle of the electrode on the fluid mixing is studied.The maximum mixing efficiency is 90.8% when the electrode circumferential angle is 35°,when the circumferential angle of the electrode is 30°,the effect of the electrode length on the fluid mixing is studied,The maximum mixing efficiency is about 89.9% when the electrode length reaches about 11?m.