Dispersion coefficient in an electro-osmotic flow of a viscoelastic fluid through a microchannel with a slowly varying wall zeta potential

摘要: The dispersion coefficient of a passive solute in steady-state pure electro-osmotic flow (EOF) viscoelastic liquid, whose rheological behaviour follows the simplified Phan-Thien–Tanner (sPTT) model, along parallel flat plate microchannel, is studied. walls microchannel are assumed to have modulated and low potentials, which vary slowly axial direction sinusoidal manner. field required obtain was solved using lubrication approximation theory (LAT). solution electric potential based on Debye–Huckel for symmetric electrolyte. viscoelasticity fluid observed notably amplify distribution effective coefficients due variation potentials walls. problem formulated two cases: when Debye layer thickness (EDL) order unity (thick EDL) limit where EDL very small compared with height (thin limit). Due coupling between nonlinear governing equations sPTT they were replaced by their approximate linearized forms regular perturbation technique. Here amplitude function potentials. Additionally, numerical also obtained solution, showing excellent agreement . Note that primarily depends Deborah number, ratio half-height length,