A novel Koch fractal micromixer with rounding corners structure

We study mainly the rounding structure of the micromixers based on Koch fractal. The mixing efficiencies of primary fractal micromixer (PFM) and secondary fractal micromixer (SFM) are compared. SFM shows better mixing performance. The mixing efficiency exceeds 90% at four different Reynolds number (Res). After rounding the corners of the secondary fractal micromixer (RCSM), the mixing efficiency of the micromixer decreases slightly. But it is still better than PFM, and the pressure-drop of the RCSM is significantly reduced compared to SFM. Especially at Reynolds (Re) = 100, the pressure-drop is changed from 21295 Pa for the SFM to 12789 Pa for the RCSM. The effect of RCSM on reducing pressure-drop is obvious. The analysis of the velocity fields of the RCSM is conducted to investigate the factors that may effect the pressure-drop with the rounding corners, and the vortexes occupy a larger range of the sections A–A′ and B–B′ than SFM. The pressure-drop caused by rounding corners will be of great significance in bioengineering.