Dispersion in composite porous medium with homogeneous and heterogeneous chemical reactions

Abstract

The effect of homogeneous and heterogeneous reactions on the dispersion of a solute in a composite porous medium between two parallel plates is studied. The solution approach suggested by Taylor [2] is generalized for the present model. The Brinkman model is used to define the flow through the porous medium. The fluids in both the regions of the parallel-plate channel are incompressible and transport properties are assumed to be constant. The closed-form solutions are obtained in both the regions of the channel. The results are tabulated for various values of viscosity ratio, pressure gradient, and porous parameter on the volumetric flow rate and the effective Taylor dispersion coefficient. It is found that for a homogeneous chemical reaction, the effective Taylor dispersion coefficient decreases as the reaction rate parameter and porous parameter increase. The validity of the results obtained for a composite porous medium is compared with the available porous medium results for a one-fluid model and the values tallied for the small values of porous parameter. Also a two-fluid model in the absence of a porous matrix is compared with the available one-fluid model and good agreement is found. © 2011 Wiley Periodicals, Inc.