Effective mixing in a short serpentine split-and-recombination micromixer

摘要

Highlights•A novel micromixer design using combined 3D serpentine and crisscross SAR structure is proposed.•Combination of vortices, fluid rotation, and chaotic advection enhance the mixing in the micromixer.•A mixing index of 0.87–0.99 is achieved with a very short length (1500μm) in a wide Re range 0.1–120.•The micromixer attains a maximum mixing index of 0.99 within 38% of the total length at Re ≥40.AbstractA micromixer with a three-dimensional serpentine split-and-recombination structure is proposed to provide a high mixing index in a short length, even at low Reynolds numbers. The fluid flow and mixing performance were analyzed numerically using three-dimensional Navier-Stokes equations and the convection-diffusion equation for mass transport in a Reynolds number range of 0.1–200. The mixing performance is represented by the mixing index, which is defined using the mass fraction variance of mixing fluids in a plane. The overall mixing performance of the proposed micromixer is compared with that of previous micromixers. The effects of the number of mixing units on the mixing performance were estimated. A parametric study was performed using five geometric parameters of the micromixer. The proposed micromixer shows mixing indices larger than 0.87 throughout the Reynolds number range in a short length of 1500μm, which is hardly achieved in previous micromixers.