Numerical characterization of simple three-dimensional chaotic micromixers

• Two representative types of 3D micromixers were numerically investigated to determine their individual chaotic mechanism.
• The mixing performances of TSMC, TSML and GSMUT are comparably superior to those of GSMMO and GSMMT beyond Re = 30.
• The chaotic mechanism was identified as alternating rotation for TSMC and continuous rotation for TSML, respectively.
• The mechanism was identified as planar stretching for GSMMO as well as GSMMT, and 3D stretching for GSMUT, respectively.

Two representative types of three-dimensional micromixers, i.e. the 3D serpentine micromixer and the square-wave micromixer with cubic grooves, are attractive designs due to their simple fabrication and efficient mixing performance. The flow and mixing characteristics of these five mixers of two types were numerically investigated for a wide range of Reynolds numbers: 8–160. The mixing quality and pressure drop of them were evaluated. TSMC, TSML and GSMUT present their comparable superiority to GSMMO and GSMMT beyond the Reynolds number of 30. The visualization of the flow and mixing was conducted for all mixers. Therefore, the chaotic advection mechanism was identified as alternating rotation for TSMC, continuous rotation for TSML, planar stretching for GSMMO as well as GSMMT, and 3D stretching for GSMUT, respectively.