Narges Jafari Ghahfarokhi - PhD Student, Department of Mechanical Engineering, Isfahan University, Isfahan, Iran.
Morteza Bayareh - Associate Professor, Department of Mechanical Engineering, Shahrekord University, Shahrekord, Iran.

Micromixers have many applications in engineering, medicine, and biology. The use of micromixers is essential to improve flow mixing in microchannels due to the low Reynolds number. In the present study, a new passive micromixer with a spiral channel is proposed, inspired by the shape of real rivers. Accordingly, the mixing process for non-Newtonian fluids is performed using COMSOL Multiphysics ۵.۴ software. Mixing of non-Newtonian fluid is examined using Carreau-Yasuda model for different values of power index include ۰.۱, ۰.۳۵۶۸, ۰.۷, ۱, ۱.۲, ۱.۵, and ۱.۷ and three inlet velocity of ۷۵, ۱۰۰, and ۲۰۰ mm/s. The results show that for shear-thinning fluids, mixing efficiency increases with decreasing power index, but for thick shear fluids, mixing efficiency decreases with the power index slightly. Also, as the velocity enhances, the mixing efficiency increases, so that for the smallest power index and velocity of ۲۰۰ mm/s, the mixing efficiency is enhanced by ۸.۴۲%.

Passive micromixer, Spiral micromixer, Mixing efficiency, Non-Newtonian fluid.