Enhancement of the mixing efficiency of double T-shaped micromixers using a combined passive scheme

Abstract

Corrugating channel walls and using cylindrical elements can be employed as a combined technique to improve mixing in micromixers. In this study, the mixing process in three-dimensional double T-shaped micromixers with mixing wavy-walled channel in the presence of cylindrical elements is simulated. The objective is to investigate the effects of the geometry of wavy walls and cylindrical elements on the mixing and hydraulic performance of micromixers at a wide range of Reynolds numbers from 10 to 110 and a Schmidt number of 500. Accordingly, the corresponding Peclet numbers vary between 5000 and 55,000. Six different micromixers including double smooth-walled, in-phase wavy-walled, and opposite-in-phase wavy-walled micromixers without elements and with the presence of elements are considered. The results show that the wavy walls significantly increase the mixing index. However, the extent of this effect depends on whether the waves on the channel walls are in-phase or opposite-in-phase. Moreover, the use of cylindrical elements can considerably enhance the mixing efficiency of wavy channels compared to smooth ones. This positive effect increases with the increase in the Reynolds number. Also, the figure-of-merit (FoM) values over 1 illustrate the excellence of the proposed configurations. FoM touches the amazing value of 1.96 in the in-phase micromixer with element at Re = 20.