Microstructured mixers for gas-phase processes - Manufacture, characterization and applications

摘要

The extremely high mixing quality reached by microstructured mixers in diffusion mixing under laminar flow conditions, as well as in mixing under turbulent flows is attributed to short mixing paths. The design of the micro devices and mixing volumes determine the flow condition to be achieved. In devices fabricated according to the multi-lamination principle, for instance, both laminar and turbulent mixing may take place due to the generally large mixing volumes. In microstructures, where the mixing volume is only a bit larger than the supply channels of the fluids, the mixing quality is dependent on diffusion or secondary flow, which may improve the mixing results. Commonly, the latter mixers can be scaled up by multiplying the mixing geometry (numbering up of the devices). As very rapid reactions between the mixed media frequently occur in the gas mixing range (e.g., combustion reactions) and turbulent flow is preferred, the present contribution primarily deals with mixers designed by the Institute for Micro Process Engineering (IMVT) on the basis of the multi-lamination principle. Among the key aspects covered are the manufacture of the pressure-resistant metal devices by the microstructurization of foil bands and the characterization of these devices by determining their mixing qualities in the gas phase. Studies carried out to assess the suitability of these mixers as flame arresters are also presented. Some model applications will be highlighted.