New insights into fluid mixing in micromixers with fractal wall structure

Microfluidics is thought to have a high development potential and a wide range of applications in biomedical research. The design of micromixers has gotten a lot of attention because they are such a crucial aspect of microfluidic devices. The passive micromixer has the advantages of simple construction and steady performance over the active micromixer. In this paper, a fractal wall micromixer is proposed, and the flow characteristics and mixing process of the secondary fractal double wall micromixer are studied using intuitive flow patterns and quantitative calculation methods. The results show that the mixing efficiency of secondary fractal wall is higher than that of primary fractal wall, and with the increase of h, the mixing efficiency and pressure drop begin to decrease gradually. When there is a secondary fractal wall structure on both sides, when Reynolds number (Re) = 0.1, the mixing efficiency of the outlet can reach 95%, and when Re = 100, the mixing efficiency of the outlet can reach 99%, almost complete mixing. The fractal wall micromixer has good mixing effect and shows great application potential in chemical engineering and biological engineering.