Comparative assessment of mixing characteristics and pressure drop in spiral and serpentine micromixers

Abstract

In this paper, numerical simulations are carried out to analyze the mixing performance and pressure drop of water and ethyl alcohol in a spiral micromixer for Reynolds number in the range of 1 ≤ Re≤100. The characteristics are also compared with those for serpentine and straight micromixers by keeping the total flow length equal. It reveals that at lower Re ( = 1), the values of mixing index are almost same for all the micromixers, For higher Re, spiral micromixer provides better mixing than that of serpentine and straight micromixers, because of the formation of secondary Dean vortices. For straight micromixer, the mixing index decreases monotonically with Reynolds number. However, contrasting features are observed for both spiral and serpentine micromixers at higher regime of Re. The mixing index first decreases with Re and then increases although the values of critical Re beyond which the mixing index increases are different for spiral and serpentine micromixers. The pressure drops for all three micromixers are almost the same at lower values of Re, while the pressure drops for spiral and serpentine micromixers are almost equal and the values are slightly higher than those of straight micromixer at higher Re.