Transport of reactive solutes in unsteady annular flow subject to wall reactions

The present paper concerns with the dispersion process in steady and oscillatory flows through an annular pipe in presence of reversible and irreversible reactions at the wall. Method of homogenization, a multiple-scale method of averaging, is adopted for deriving the effective transport equations. The main objective is to look into the effect of aspect ratio of the annular pipe on the dispersion coefficient due to the combined effect of axial convection and radial diffusion in steady and oscillatory flows along the annulus, subject to the kinetic reversible phase exchange and irreversible absorption at the outer wall. Results demonstrate that upto a certain critical value of aspect ratio, dispersion coefficient increases with increase of aspect ratio when the wall is retentive, though the wall inertness may lead to decrease of dispersion coefficient with increase of aspect ratio. The results would be useful to the medical practitioners working in the domain of catheterized artery.