Investigation on the splitting-merging passive micromixer based on Baker's transformation

Passive micromixers have a wide applications due to no need of external energy and moving parts. Stratification of chaotic advection is an important mechanism to enhance mixing efficiency in micromixers. A novel Baker-based micromixer with ceaseless stratification was designed on the basis of chaotic theory. In order to illustrate the perfect mixing efficiency and mixing mechanism in such a micromixer, numerical simulations were carried out, and comparisons with other splitting-merging micromixers named Helical-mixer and Smale-mixer are conducted. The numerical results show us that, the Baker-mixer has more excellent mixing efficiency at low Reynolds number because of more-folds of interfacial areas between two streams caused by stratification effect. However, the mixing efficiency of Baker-mixer is not a patch on that of Smale-mixer at high Reynolds number. The reason should be that, bending channels in Smale-mixer can induce secondary flow to enhance convection mixing. LIF experiments were conducted and the mechanism of chaotic mixing in Baker-mixer and validity of numerical method are verified by the good agreement between numerical results and experimental results. A powerful auspice for the design of the high-performance chaotic passive micromixer is provided.