Presentazioni e Articoli Tecnici

The method to derive upscaled expressions for the dispersion coefficients for reactive flow in a porous medium uses a periodic unit cell (PUC), which consists for instance of a spherical grain in a cube, but nothing prohibits defining more complex PUC's. Homogenization leads to a coupled system of equations where the flow is described by Stokes equation and the concentration fluctuation is described by a convection diffusion source term equation. We show that the commercial finite element software COMSOL can be readily used to compute longitudinal and transversal dispersion coefficients in 2-D and 3-D; this makes homogenization accessible to the engineering practice. The results are for the first time compared with experimental data of the dispersion coefficient versus Péclet number; there is good agreement.