Slippage effect on the dispersion coefficient of a passive solute in a pulsatile electro-osmotic flow in a microcapillary

The hydrodynamic dispersion of a neutral solute released into a pulsatile electro-osmotic flow in a microcapillary that is affected by slippage at the wall (modeled by the Navier slip condition) is studied theoretically. The long-time Taylor dispersion is analytically derived using the homogenization method with multiple scales. The results indicate that the effective dispersion coefficient depends on a dimensionless slip length, an angular Reynolds number, the amplitude of the oscillatory component of the external electric field, and an electrokinetic parameter that relates the radius of the microcapillary with the Debye length. Our results suggest that in the presence of the Navier slip condition, the dispersivity is maximized by up to two orders of magnitude compared with that obtained through the classical no-slip condition.