Micromixing of Non-Newtonian Fluids in a Passive Micromixer with an Inner Eccentric Cylindrical Obstacle

Micromixers have various applications in chemical, biological, and medical industries. Even though many liquids experience non-Newtonian behavior, a few investigators have examined their micromixing. In the present paper, the mixing performance of shear-thinning non-Newtonian liquids in a passive micromixer with an inner eccentric cylindrical obstacle is assessed numerically by employing the Carreau-Yasuda model. The time evolution of the mixing process is analyzed and the influences of the power-law index, inlet velocity, and relaxation time on the mixing index are evaluated. It is demonstrated that the mixing index is improved with time and reduces with the inlet velocity. The pressure drop is a descending function of inlet velocity. Besides, the diffusion coefficient does not have a considerable impact on the mixing index. The results reveal that the mixing index of shear-thinning fluids is larger than that of a Newtonian one under the same conditions. For instance, MI = 63.7% and 33.1% when n = 0.1 and 1, respectively.