Analysis Of Velocity And Experiments For Mircofluid Flow Induced By Alte Current Electroosmosis

Microfluid pumping is an important branch of microfluidic system research. Compared with other approaches, AC Electroosmosis (ACEO) pumps have many advantages, such as simple structure, low cost, no moving parts, low voltage, no electrolysis, no bubble, stability fluid flow, and easily to be integrated into microfluidic systems, which attract more and more people's recognition in last decades. It shows that experimental velocity of ACEO is much smaller than theoretical predicted velocity values based on classical electric double layer (EDL) theory, so it becomes a hot issue to focus on the flow characteristics, interpret its mechanism, analyze influence factors and modify the calculation formula of ACEO velocity.This paper summarized the research status of MEMS and micropump all over the world, then the ACEO pumping technology is compared with other approaches, such as mechanical micropump and DC electroosmosis pumps. The mechanism of electric double layer and electroosmosis flow is analyzed based on equivalent electric double layer model with Stern layer thickness and electrode roughness in consideration. According to the correction, ACEO flow velocities based on symmetric, asymmetric and parallel arrays electrodes have been revised. Relative errors between calculation velocities via two models and experimental results are compared to validate the correction. Besides, the influence of correction coefficient is discussed to the electroosmosis's velocity expression.Based on the theoretical analysis, the mathematical physical models of asymmetric and parallel arrays electrodes are proposed and simulated. By solving Laplace equation and Navier-Stokes equation, electric potential and flow field distribution are solved. The influences of potential voltages, frequency, bulk conductivity, electrode physical dimension, microchannel height and electricthermal to ACEO velocity are studied.Experimental ACEO flow rate applied in traveling wave electric field agrees with simulation result very well, showing validity of the equivalent double layer model. Not only the influences of voltage, frequency, conductivity, and plant geometry to slip velocity is studied, but also the Joule heating effect at relative high frequency is discussed to complete our theory, and it can. provide a theoretical and experimental basis for mcropumping and microfluid manipulation.