A high-efficiency planar micromixer with convection and diffusion mixing over a wide Reynolds number range

Over a wide Reynolds number range (0.1 <= Re <= 40), the new planar obstacle micromixer has been demonstrated over 85% mixing efficiency covering the mixing improvement in both convection-enhanced (higher Re flow) and diffusion-enhanced (lower Re flow) mechanisms. Mixing behavior between two operation windows was investigated by numerical simulations and experiments. For the adaptive design, numerical simulations and Taguchi method were used to study the effect of four geometrical factors on sensitivity of mixing. The factors are gap ratio (H/W), number of mixing units, baffle width (W-b) and chamber ratio (W-m /W). The degree of sensitivity using the Taguchi method can be ranked as: Gap ratio > Number of mixing units > Baffle width > Chamber ratio. Micromixer performance is greatly influenced by the gap ratio and Reynolds number. Beside the wide Reynolds number range, good mixing efficiency can be obtained at short distance of a mixing channel and relatively low-pressure drop. This micromixer had improved both complex fabrication process of multi-layer or 3D micromixers and low mixing efficiency of planar micromixer at Re < 100. The trend of the verified experimental results is in agreement with the simulate results.