Chaos-induced charge electro-osmosis of Phan-Thien-Tanner fluids around a metal cylinder

Efficient manipulation and mixing of viscoelastic fluids at the microscopic scale is essential for advancing various applications in biomedical and chemical analysis. Chaos-induced charge electro-osmosis (CICEO), which utilizes irregular vortex flow fields generated by electric field-induced charges to improve mixing efficiency, is a promising solution. Herein, a two-dimensional cavity filled with an electrolyte solution with a polarizable conductive cylinder in the center of the cavity is considered. The simplified Phan-Thien-Tanner constitutive model is used to accurately describe the viscoelastic behavior of the fluid inside the microfluidic mixer. The fully coupled Navier–Stokes (NS) and Poisson-Nernst-Planck equations are solved using numerical simulations. The results show that both the thin electric double layer and high electric field strength promote CICEO behavior. The near-wall charge density at κ̃ = 1000 is 32 154, which is about 1763 times higher than that at κ̃ = 10. The peak velocity is about 1 for Ṽ = 1, while it is about 130 for Ṽ = 30.