Electrokinetic flow of fluids with pressure-dependent viscosity and slip-dependent zeta potential

Abstract This paper investigates the electrokinetic flow and electrokinetic energy conversion efficiency(EKEC) of fluids characterized by pressure-dependent (P.D.) viscosity and slip-dependent (S.D.) zeta potential within a slip channel. Using the exponential pressure-viscosity relationship, we derive the electrokinetic flow characteristics of the fluid by solving the continuity and two-dimensional momentum equations with the perturbation method. A systematic study is then conducted on the influence of S.D. zeta potential and the effect of P.D. viscosity on the pressure, viscosity, velocity, streaming potential, and electrokinetic energy conversion efficiency. The results show that the P.D. viscosity effect increases the pressure and the fluid viscosity, but reduces the electrokinetic energy conversion efficiency. The S.D. zeta potential effect enhances the pressure, fluid viscosity, axial velocity, vertical velocity, and streaming potential, and markedly improves the EKEC. The results reveal that Case II (pressure-independent viscosity and slip-dependent zeta potential) achieves a higher energy conversion efficiency than the other three cases. In the pressure-dependent viscosity cases, the slip-dependent zeta potential effect improves the maximum conversion efficiency from 7.5% to 10.9%, an improvement of 45.33%. This study provides a theoretical reference for modeling the fluid flow involving pressure-dependent viscosity and slip-dependent zeta potential.