Reference: D.P. Bentz and N.S. Martys, Transport in Porous Media, 17 (3) 221-238 (1995).

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Hydraulic Radius and Transport in Reconstructed Model Three-Dimensional Porous Media

Dale P. Bentz and Nicos S. Martys

Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899-8621 USA


Methods for reconstructing three-dimensional porous media from two-dimensional cross sections are evaluated in terms of the transport properties of the reconstructed systems. Two-dimensional slices are selected at random from model three-dimensional microstructures, based on penetrable spheres, and processed to create a reconstructed representation of the original system. Permeability, conductivity, and a critical pore diameter are computed for the original and reconstructed microstructures to assess the validity of the reconstruction technique. A surface curvature algorithm is utilized to further modify the reconstructed systems by matching the hydraulic radius of the reconstructed three-dimensional system to that of the two-dimensional slice. While having only minor effects on conductivity, this modification significantly improves the agreement between permeabilities and critical diameters of the original and reconstructed systems for porosities in the range of 25-40%. For lower porosities, critical pore diameter is unaffected by the curvature modification so that little improvement between original and reconstructed permeabilities is obtained by matching hydraulic radii.

Keywords: building technology, conductivity, critical diameter, hydraulic radius, permeability, porous media, reconstruction

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