Numerical Study on Enhancing Microscale Fluid Mixing with Combined Fixed and Oscillating Obstacles

Efficient mixing of fluids at the microscale is a critical challenge due to laminar flow conditions and suppressed turbulence. In this study, a novel active micromixer is proposed, consisting of a series of fixed and oscillating rectangular obstacles. The effects of obstacle motion, including oscillation frequency and relative direction of moving obstacles, on mixing performance are systematically investigated while the overall geometry, number of obstacles, Reynolds number, and Schmidt number are kept constant. Three configurations are analyzed: all moving obstacles considered stationary, all moving obstacles oscillating in-phase, and moving obstacles oscillating alternatively in opposite directions. Numerical simulations are performed using a modified Incompressible Smoothed Particle Hydrodynamics (ISPH) method, which enables accurate and efficient analysis of microscale transport phenomena. The results demonstrate that the motion of obstacles significantly enhances mixing efficiency, with alternating oscillations achieving highly effective mixing. Parametric studies show that both the oscillation frequency and direction of obstacle motion play crucial roles in accelerating fluid mixing. This work provides detailed insights into the synergistic effects of obstacle dynamics and motion characteristics, offering practical guidance for designing efficient active micromixers in chemical, biological, and biomedical applications.

کلیدواژه ها:

Microscale mixing ، Active micromixer ، Fixed and oscillating obstacles ، Oscillation frequency ، Direction of motion ، SPH