Micromixers based on molecular diffusion - Micromixers Fundamentals Design and Fabrication - page 167

FIGURE 5.4
Methods for shortening the striation thickness: (a) lamination over the channel height and (b) splitting and
rejoining.
The more common technique for shortening the striation thickness is splitting the solute and the
solvent into multiple streams and rejoining them through parallel lamination ( Fig. 5.4 ). Combining
parallel lamination with geometric focusing can be a powerful concept to improve the micromixer's
performance [5] . Figure 5.5 (a) illustrates this concept. With a large number of streams, the outer
streams may experience a sharp bend during the focusing process. At small flow velocities or low
Reynolds numbers, the bend has almost no effect on the shape of the lamellae. However, at high
Reynolds number on the order of 10 or 100, secondary flow caused by inertial forces (see
FIGURE 5.5
Parallel lamination with geometric focusing: (a) concept and (b) distortion of the shape of lamellae (after [6] ).