Mixing performance of the induced charge electro-osmosis micromixer with conductive chamber edges for viscoelastic fluid

Abstract

Enhancing the micro-channel flow mixing is always a difficult problem. In this study, a micromixer based on induced charge electro-osmosis is proposed. A T-shaped micromixer, which has a chamber with conductive surfaces in the channel, is chosen. Due to the electro-osmotic effect of the induced charge, the induced potential is generated on the conductive surface. The Oldroyd-B constitutive model is chosen to characterize the flow characteristics of polyacrylamide solution, and an open-source solver named rheoTool based on the finite-volume method is used. The effect of the chamber shape, the chamber size, the conductive edge numbers in the chamber, and the applied electric intensity on the mixing efficiency are investigated. The results show that the micromixer with conductive edges in the chamber has better mixing effect because of the vortices. At the same time, compared with other shapes, the micromixer with diamond chamber has the best mixing effect, and the mixing efficiency reaches 79.51%. In addition, the mixing efficiency of one conductive edge in the diamond chamber is 4.39% higher than that of the two conductive edges chamber. It is found that increasing the chamber size will improve the mixing efficiency, and the mixing efficiency increased by 12.76% with the increase in chamber size. On the other hand, when increasing the electric field intensity from 100 to 200 V/cm, the mixing efficiency will decrease.