Mixing Analysis of Serpentine Microfluidic Mixers with Non-Rectangular Cross-Section

Serpentine or spiral shaped channels have been used in the past as a way to induce mixing in microfluidic type devices. In this approach one exploits the cross-sectional flows, also known as Dean flows, resulting from the centripetal forces experienced by the fluid as it is forced to move around a curved trajectory. However, it has to be noted that the quality of mixing is strongly dependent on the Reynolds number, with good results being achieved only at high flow rates. In this work we exploit the use of channels with asymmetric non-rectangular sections to improve the mixing quality in this type of microchannels. Alternating the orientation of the non-rectangular cross-section between the serpentine channel segments generates more complex fluid flows with a positive impact on the performance of the mixers. The fluid flows characteristics are determined numerically from computational solutions to the Navier-Stokes equations and the concentration - diffusion equation. We found that the performance of these mixers exceeds that of unmodified channels and we currently assess their performance relative to other state of the art methodologies.