Effect of secondary flows on contaminant dispersion with weak boundary absorption

The present analysis brings out the interaction of curvature and a weak wall absorption parameter on the dispersion process using Taylor analysis. A perturbation series solution has been obtained td find the values of the effective dispersion coefficient. The constraints imposed by the perturbation techniques have been removed using a numerical scheme based on spectral method. Results are found to be applicable for a time at which the Taylor dispersion model holds. It has been observed that in the interphase transport of reactive contaminants the effective dispersion coefficient is significantly different from that of Taylor due to the wall absorption parameter. The results corresponding to the straight tube are verified with the published results, and those obtained from the perturbation and spectral techniques are found to be comparable. The restriction of the present analysis is confined to the effect of weak wail absorption under laminar flow conditions This restriction needs to be relaxed. For moderate or large values of the absorption parameter a generalized dispersion model has to be resorted to. (C) 1997 by Elsevier Science Inc.