Numerical simulation of passive micromixers with curved mixing units: A study of improving the mixing quality of inlet gases in different Reynolds

Mixing different or identical fluids together plays an important role in many microstructures, so it is important to study the quality of mixing in microchannels. Numerical study of oxygen and nitrogen mixing in passive three-dimensional micromixer was performed by finite element method and the effect of Reynolds number, type, number and width of mixing units and obstruction in the flow path on mixing quality and pressure drop was investigated. While most previous studies have been on the mixing of liquids, in this study the mixing of gases in simple micromixers, as well as micromixers with mixing units, has been investigated. For this purpose, two new types of micromixers named A and B with new and multiple mixing units have been introduced. Mass performance evaluation of the new model's A and B with helical mixing units, compared to the base model without the mixing unit shows that the new models have a higher performance than the base model as micromixer A with five mixing units, in Reynolds 110, compared to the base model. Improves mixing quality 2 times and 1.25 times better than Model B. Also, the effect of the depth of cubic barriers in micromixer B with five mixing units indicates the improvement of mixing quality compared to the unobstructed model in higher Reynolds. As in Reynolds 110 model B with five mixing units, the mixing quality is about 95%.