Modeling of Mixing Elements in Microfluids

The article is devoted to microfluidics (microhydrodynamics), a science that describes the behavior of small (micro- and nanoliter-sized) volumes and flows of liquids. Microfluidic reactors have become widely used in various fields of science: medicine, special chemistry, biochemistry, nuclear chemistry, and many others. They are popular due to the increased mass and heat transfer they provide, better process intensification, and, as a result, high product yield. The most important elements of microreactors are the mixing zone, which ensures destabilization and swirling of flows for the purpose of mixing them, and the reaction zone (serpentine channel), calculated depending on the kinetics of a specific reaction. The work is dedicated to the microfluidic industry and reflects one of its most important aspects, i.e., mixing. Mixing in such reactors occurs in a laminar mode and is carried out exclusively by molecular and convective mass transfer. The main mixers used in microreactors, such as T-shaped and Y-shaped mixers, and typical mixing cells used in a cascade design, are investigated. As a result of the conducted research, the most successful mixer options are identified and the required microchannel length for complete mixing of the initial reagents for each of them is calculated. In order to improve the efficiency of the process, standard micromixers are proposed that allow for a reduction in the channel length required for complete mixing of the reagents. The most successful micromixer is identified and cascade modeling is carried out; the minimum number of cells sufficient for a successful reaction is identified. In this work, the kinetics of a specific process is not considered; the length of the reaction channel directly depends on the specific reaction.