In this study, the geometrical parameters of a micromixer with gaps and baffles are optimized by using design of experiments based on the Taguchi method. Design of micromixers with gaps and baffles to increase the mixing efficiency is crucial in various biological applications such as DNA analysis. The arrangement of gaps and baffles significantly affects the fluid flow structure and mixing. In some cases, arrangement of obstacles outweigh design of framework. The effects of four design parameters are investigated on two important characteristics of a mixer namely mixing efficiency and pressure drop. A weighted profit function is defined to combine these two characteristics. The computational fluid dynamics (CFD) is used to simulate the fluid flow and mixing in three-dimensional models. For this numerical study, the commercial CFD package, COMSOL, is used. The analyses of the numerical results are then shown in signal to noise (S/N) ratio plots indicating which combination of parameters leads to a maximum profit. It is found that a micromixer with the optimized geometry compared to its initial design increases the mixing index by 15% on average in the Reynolds numbers ranging from 1 to 10.

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