Swirl-inducing inlet for passive micromixers

Abstract

This paper proposes a swirl-inducing inlet as a simple and effective method to improve fluid mixing in passive micromixers in the range of Re > 20. A pair of antisymmetric barriers are placed in the mixer inlets to generate angular momentum in the flow and induce a swirling flow structure. It can be applied as a small modification to many conventional passive mixers that have counter-inlets such as the T-shaped channel. In this paper, we show the effectiveness of the proposed inlet through numerical simulations of the mixing process in two representative passive micromixers: the T-shaped micromixer with rectangular cross section and the three-dimensional serpentine micromixer with L-shaped repeating units. The simulations show that the proposed inlet can successfully generate a strong swirling flow and provide considerable mixing improvement in both types of micromixers tested at Re = 20–150, where the mixing is enhanced by greater than a factor of two based on the mixing index.