(129e) On the Scalability of Microstructured Multilamination Mixing Devices

Microstructured devices posses numerous advantages on the laboratory scale. The development of microstructured devices for industrially relevant throughputs is rarely reported, and the corresponding upscale is still a challenging task.

In the field of microstructured mixing devices, there are numerous devices suggested for small throughputs; for higher throughputs only few designs are reported.

We have examined multilamination type mixers (figure 1), which consist of a stack of micromachined foils with ten geometrically identical channels per foil. The respective stacks differ in the number of foils per stack. The system of 20 to 240 micromachined channels divides two fluid flows (volumetric flow ratio 1/1) into the corresponding number of substreams. Mixing occurs in a mixing chamber at the exit of the microchannel system. The mixing chamber was kept constant for all experiments and showed no influence on the experimental results.

Figure 1: Construction principle of microstructured V-type mixers: (a) stainless steel foils with microchannels and (b) stack of stainless steel foils.

In this contribution we report on the scalability of the examined mixers with respect to ?mixing quality' and pressure drop. The ?mixing quality' upscale assumptions are validated by means of the ?iodide iodate reaction system', a parallel competitive reaction system, which produces the more iodine the worse the mixing performance is. The amount of iodine is reflected by the absorbance value in the UV spectrum centered at 353 nm (Figure 2).

Figure 2: Experimentally obtained absorbance values over total mass flow for stacks of micromachined foils with different number of layers.

When the absorbance values are depicted in terms of linear velocity of the fluid flow at the exit of the microchannel system all examined stacks show the same mixing performance (figure 3).

Figure 3: Experimentally obtained absorbance values over linear fluid velocity for stacks of micromachined foils with different number of layers.

It is shown that the multilamination type mixers can be scaled by ?numbering up' the layers that are used for multilamination obtaining the same ?mixing quality'.