transport of reactive species in oscillatory annular flow

The present article purposes to investigate the solute dispersion through an annular pipe in the presence of heterogeneous chemical reactions among the species and wall of the annulus. the solute is considered to experience a kinetic reversible phase exchange with the inner wall layer and irreversible absorption into the wall. two kinds of oscillatory flow (poiseuille and couette flow) are considered in order to track the complex interactions between the velocity distributions and the reaction parameters. the method of moments as proposed by aris-barton is used to determine the apparent dispersion coefficient. the moment equations has been solved by using a standard finite difference implicit scheme, valid for small as well as large times. dispersion coefficient due to the combined effect of reversible and irreversible reactions has been discussed in a variety of flow situations. dispersion coefficient may be enhanced owing to the reversible and irreversible heterogeneous reactions in the boundary. on the basis of flow characteristics, radius ratio provides a mixed behaviour of the dispersion coefficient. dimensionless mass proves to be an increasing function of reversible and irreversible boundary reaction parameters.