Micromixers based on chaotic advection - Micromixers Fundamentals Design and Fabrication - page 217

FIGURE 6.24

Micromixer with both slanted and herringbone structures on both top and bottom walls.

FIGURE 6.25

SOR with slanted structures on both top and bottom walls.

is similar to the SHM design, this mixer only works well in the intermediate range of Reynolds number
(10 100).

Inspired by macroscale Kenics mixer, Kim et al. [36] improved the design of Stroock et al. [26]
with embedded barriers parallel to the flow direction. This barrier forces the flow to change the original
elliptic mixing pattern [26] to a hyperbolic pattern [36] ( Fig. 6.26 ). The micromixer was fabricated in
PDMS. The mixing channel of this design is 240

< Re <

m m in width, 60 m m in depth, and 21 mm in length.

The barriers have a cross-section of 40 m. Experimental results show a clear improvement

in mixing efficiency compared to the SGM design. Based on numerical simulation, the performance of
BEM is slightly lower than that of the SHM. Avariety of designs can be derived from the basic concept
shown in Fig. 6.26 . Two or more barriers can be used. The barriers can be placed asymmetrically inside
the mixing channel. Alternating one and two barriers may lead to an even more chaotic flow pattern.

m m 30 m