Numerical and experimental analysis of effective passive mixing via a 3D serpentine channel

In laminar mixing, geometry can enhance advective mixing. In this study, a 3D serpentine structure is proposed for effective mixing at low Reynolds numbers. Mixing performance of 3D channel fabricated by 3D printer was compared with that of straight and 2D serpentine channels via numerical simulation and experiments. In simulation results, mixing in 3D channel is the most efficient. Higher flow variability for 3D channel leads to the up, down, left, and right movements of transverse flow. However, flow in 2D channel moves in the left and right of the cross section. In addition, Dean flow generated in the bend enhances the mixing performance. While increasing the Reynolds numbers from 5 to 30, the mixing index was also checked in both a numerical simulation and experiment. The proposed 3D serpentine structure could have potential for mixing applications such as a minimized biochip system at low Reynolds number.