Meander mixer

Version (b). This design of meander mixer was actually realized. It refers to a structure with a large number of mixing elements which was micro-machined by precision milling in a plastic material [47]. Irreversible sealing of the channel was accomplished by insertion of a thin PMMA foil via solvent bonding. 

Figure 1.150 Residual portion of particles remaining in the meander mixer for K = 200 [47].

Figure 4.16 Interface stretching factor in meander mixer as function of the number of loops and Dean number [28]. (Adapted with permission from Wiley.)...

Figure 11.6 A 4-element meandering mixer and its dimensions. (From Jiang, F. et al., AlChE, 50, 2297, 2004.)...

Figure 1.137 Mixing efficiency versus the meandering ratio s/w at Pe = 2600 and at two different Re for a set of zig-zag and straight-channel micro mixers. Re = 0.26 (triangles) Re = 267 (circles) [59] w = channel width, L = channel length (by courtesy of ACS).

Here, micro mixers with a repeatedly curved, i.e. meander, design are considered... 

Mixer type Meander channel micro mixer Channel width 200 pm... 

Figure 1.152 Micro photographs of the mixing patterns in the meander micro mixer for different Dean numbers and positions [47],...

M 70b] [P 63] Photometric concentration profiles were obtained for mixing of 50 mW reactant solutions at 25 °C and K = 246 in a meander micro mixer close to the inlet (see Figure 1.153) [47]. At the start of the mixing process only one lamella is visible, corresponding to about 10 mM reaction product. Further downstream, the next profiles provide a multitude of lamellae, which represent between 2 and 24 mM product. At still further positions in the meander channel, more homogeneous flow patterns are yielded and the product content is increased to between 15 and 28 mM. Finally, the concentration increases to values close to 50 mM which indicates complete mixing. 

A mixing reactor was developed by Hoechst AG at the end of the 1970 s, whose square cross-section was filled with meander-shaped heat exchange tubes [382, 385], see Fig. 8.8. The individual coils of piping are inclined in an opposing sense to the neighboring position, whereby a network results, which is similar to that of the Sulzer SMX mixer. This device has been commercialized by Sulzer AG as the SMR mixer. 

Dean flow as a static mixer The use of the fluid inertia across a curved channel can create turbulence. The flow of fluids in the meandering channels undergoes mixing due to the inertia of the fluid in the flow direction. An example is shown in Figure II.6, while the Dean number is defined in the side bar. 

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