Modeling active micromixers with multiple microstirrers using Smoothed Particle Hydrodynamics

Smoothed Particle Hydrodynamics method is used to explore the effects of design parameters on the mixing efficiency of two types of active micromixers. First, the complex flow field and the mixing process of two separated fluids in a square mixing chamber with nine symmetric microstirrers are simulated. The influence of design parameters such as the microstirrer rotation arrangement and the angular velocity of the microstirrer on the mixing performance are investigated. Mixing index parameter on ten control points is calculated and the average mixing index is compared for different cases. Simulations illustrate that the rotation arrangement of microstirrers is a key parameter in the mixing process. Then, a parametric study is performed for a horizontal and a Y-shape active micromixer where the influence of the length, the angular velocity, the rotation or the oscillation movement of the microstirrer, the inlet Reynolds number, and the inlet stream angle is investigated. It is also illustrated that the inlet Reynolds number and the Struhal number are the prominent parameters that affect the mixing efficiency of this type of active micromixers.