Numerical and experimental investigation of Tesla micromixers with different three-dimensional herringbone structures

Laminar flow within channels at the micro- or nano-scale of the microfluidic device restricts the rapid mixing of different fluids, leading to reduced reaction velocity. In this study, different three-dimensional herringbone structures were designed to the Tesla micromixers to enhance transverse flow and vortex flow in the channels. Computational fluid dynamics (CFD) simulation results indicated that the sunken herringbone structure provided the most significant enhancement in mixing. The raised herringbone structure exhibited the best energy performance. When Reynolds number (Re) exceeded 60, the mixing indexes (MI) of the Tesla micromixers were over 90%. The improvement in mixing efficiency by both herringbone structures compensated for the weak mixing performance of the Tesla structure at lower Reynolds numbers (Re=0.2–30). Additionally, the mixing experimental results verified the accuracy of the simulation results. This study could provide guidance for improving the mixing performance of micromixers over a wide range of Reynolds numbers (Re=0–100).