Abstract
The fluid flow characteristics in microchannel were influenced by its sidewall surface morphology. This paper investigated the effects of sidewall roughness on mixing performance of zigzag microchannels. Five microchannels with sidewall roughness from 0.225% to 1.623% were firstly fabricated through two-step CNC micromilling operation. Then, the actual sidewall profiles were acquired and imported into the three-dimensional models. Numerical simulation and experimental validation were conducted with Reynolds number from 0.1 to 100. It was found that the sidewall roughness had significant effects on mixing performance when Re ≥ 50, while the effects would be negligible when 0.1 < Re < 50. The sidewall roughness caused higher flow resistance and simultaneously brought the effect of characteristic length shortening. With sidewall roughness of 1.208% and 1.623%, the central fluids could achieve higher flow velocity than in the smooth microchannel. Therefore, the chaotic advection was intensified and excellent mixing performance was obtained. The contribution of this research enlightens that it is unnecessary to pursue smooth microchannel micromixers manufactured by precision manufacturing process which is usually with low productivity and high cost. The microchannels with sidewall roughness higher than 1.208% are more favorable for the excellent mixing performance.
Published Version
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