Percolation in two-scale porous media

Two-scale porous media are generated by filtering a Gaussian random correlated field with a random correlated threshold field. The percolation threshold and the critical exponent ν are derived with the help of a finite-size scaling method. The percolation threshold for the three-dimensional media is a decreasing function of the variance and correlation length of the threshold field. A simplified model predicts these trends in 3d; moreover, it suggested some effects in 2d which were all numerically verified. Received 17 August 2000     

Permeability of Self-Affine Fractures

The permeability of self-affine fractures with various roughness exponents H is investigated by direct three-dimensional numerical simulations. A scaling behavior with an exponent H is exhibited in the self-affine scale range. Permeability can be related to the fractional open area and to the percolation probability by simple models.     

Smouldering in fixed beds of oil shale grains. A three-dimensional microscale numerical model

A three-dimensional, microscale numerical model for the simulation of smouldering in fixed beds of solid fuels is presented. It solves the local governing equations, and therefore explicitly accounts for the coupling of the transport and reaction mechanisms on the microscopic scale. This article describes the conceptual and numerical apparatus and provides illustrative examples of calculations. Extensive applications will be presented in two companion papers.     

On the Influence of Boundary Conditions when Determining Transport Coefficients from Finite Samples of Porous Media: Assessment for Tomographic Images of Real Materials

Transport in Porous Media - The increasing access to 3d digital images of porous media provides an ideal avenue for the determination of their transport properties, by solving the governing...