Numerical investigation of Y-shaped micromixer with tree-shaped obstacles

Fossil fuels are still the majority used source of energy today. The use of renewable energy sources such as wind and solar as alternatives to fossil fuels is being encouraged due to limited resources and the non-environmental friendly nature of fossil fuels. Recently, studies of biodiesel in engines instead of fossil fuels have increased due to microfluidics theory. In this connection, chaotic micromixers are commonly preferred in biodiesel synthesis applications to provide a continuous process. The assumptions given are usually that fluid dynamics problems becoming invalid at microscale flows due to the creation of high surface-area-to-volume ratio compared to the conventional channels. Therefore, governing equations are redescribed for incompressible Newtonian fluids. In this study, the mixing efficiency of a Y-shaped passive micromixer with tree-shaped obstacles using water and acetone was investigated by computational fluid dynamics (CFD). The Micromixer was modified from the first design between the inlets and the first obstacle. Concentration distributions showed that homogenous mixing was observed for the design with obstacles while fluids mixed in a small region for Y-shaped micromixer without any obstacles. Mixing efficiency with obstacles (at Reynolds number, Re=10) was better than a standard Y-shaped micromixer without any obstacles. Performance increased with a further increase in the position of the obstacles in the channel. Overall, efficiency increased 3.1 times at the exit of the channel compared to an obstacle-free micromixer. Results indicated that the efficiency was in good agreement with the literature. The present findings may be beneficial for the development of mixing efficiency in micromixer devices such as biodiesel production applications.