Mixing In Structured Microchemical Devices

摘要

Microdevices are being used in a wide variety of applications ranging from high throughput screening of materials and catalysts to microreactors for chemical and biological syntheses to portable power generation.Despite several advantages of microscale devices, including fast heat and mass transfer, operation of these devices is non-trivial. The small length scales in these devices imply laminar flow, where molecular diffusion is the primary mechanism for mixing of fluids. Diffusive mixing compounded with short residence times imply that mixing is challenging. Furthermore, large catalytic surface areas are difficult to achieve in compact devices. Structured microreactors with small scale features, such as cylindrical posts, have recently been proposed to enhance the available surface area for catalytic reactions and potentially impart flow uniformity in static micromixers . However, a systematic study of the effect of these microscopic features on mixing is lacking. In this work we characterize the flow in the presence of microscale structures along with their effect on overall chemical reactivity. Finally, guidelines for optimization of mixing of structured microdevices are proposed.