Simulation of three-dimensional porous networks

Simulation of porous networks, with characteristics similar to those of rea l media, is essential for the study of capillary processes that take place within these substrata. The dual site-bond model (DSBM) provides a theoreti cal basis from which it is possible to adequately describe and simulate por ous networks of diverse structural properties. Following the DSBM principle s, heterogeneous 3-D cubic porous networks have been built by a Monte Carlo method. The desired topological properties of these substrata have been in troduced by considering: (i) different sizes of the Void entities (sites or cavities and bonds or throats); (ii) different connectivities (C) of the p ore elements with their neighbours, i.e. the number of throats (bonds) that surround and connect a. pore cavity (site) with its homologous entities is not constant throughout the network; (iii) geometrical restrictions, in th e sense that the sizes of the bonds that meet into a site must be of such v alues as to avoid any mutual interference. The overlapping (Omega) between the site and bond distribution functions, the connectivity (C) and the geom etrical restrictions (G), are the three fundamental factors that promote se gregation effects in the substrate. For regular networks (i.e. those of con stant C) subjected to G and high Omega, it is found that big sites: (i) pre fer big bonds as neighbours, and (ii) are less affected by geometrical rest rictions than small ones. In turn, for irregular networks of varying C subj ected to G and large Omega it is found that: (i) the smallest sites are lin ked to the biggest possible bonds thus acquiring a low connectivity, and (i i) the biggest sites adopt the maximum possible connectivity and allocate s mall and medium size bonds rather than large ones. All these particularitie s strongly influence the topology of a porous network and hence the reparti tion of fluids inside the pores during a capillary process. (C) 2001 Elsevi er Science B.V. All rights reserved.