Two methods for pore network of porous media

Abstract

SUMMARYTwo approaches of generating pore networks of porous media are presented to capture the pore fabric. The first methodology extracted pore structure from a computer simulated packing of spheres. The modified Delaunay tessellation was used to describe the porous media, and modified Nelder-Mead method in conjunction with three pore-merging algorithms was used to generate the pore size and coordination number distributions of the randomly packed spheres. The Biconical Abscissa Asymmetric CONcentric bond was used to describe the connection between two adjacent voids. This algorithm was validated by predicting pore structure of a cubic array of spheres of equal radius with known pore sizes, throat sizes and coordination number distributions. The predicted distributions of pore structure agreed well with the measured. Then, the algorithm was used to predict pore structure and permeability of randomly packed spherical particles, and predicted permeability values were compared with published experimental data. The results showed that the predicted permeability values were in good agreement with those measured, confirming the proposed algorithm can capture the main flow paths of packed beds. The second methodology generated an equivalent pore network of porous media, of which the centers of voids were located in a regular lattice with constant pore center distance. However, this network allowed for matching both main geometrical and topological characteristics of the porous media. A comparison of the two approaches suggested that the second approach can also be used as a predictive tool to quantitatively study the microscopic properties of flow through porous media.

Simulation of Dynamic Two-Phase Flow During Multistep Air Sparging

“…All these parameters can be extracted directly from packed spheres . Gao et al (2011) showed that both the pore size distribution and the coordination number distribution approximately obey normal distribution for the random close packing of particles. There is no direct proof that the pore bodies are spatially correlated in size; however, there is weak spatial correlation between the pore body size and coordination number.…”

“…The procedure for constructing an equivalent network is presented in Gao et al (2011). The main geometric and topological parameters that can be considered in the network include total number of pores in the network, average pore size, maximum and minimum pore size, standard deviation of pore size, pore spacing, parameters for characterizing the BACON bonds connecting two neighboring pores, average coordination number, standard deviation of coordination number.…”

“…According to Gao et al (2011), the flow rate in a BACON bond i-j as shown in Fig. 1 connecting pores i and j for two-phase flow can be expressed as…”

“…However, reasonable relative permeability values can be obtain by matching coordination number distribution. Gao et al (2011) proposed and validated one method of generating a 3D equivalent pore network of porous media to capture the pore fabric. This pore network can match both main geometrical and topological characteristics of the porous media including pore size distribution, coordination number distribution, and spatial correlation between pore size and coordination number.…”

“…This pore network can match both main geometrical and topological characteristics of the porous media including pore size distribution, coordination number distribution, and spatial correlation between pore size and coordination number. In addition, Gao et al (2011) introduced the Biconical Abscissa Asymmetric CONcentric (BACON) bond (Fig. 1) as a replacement for traditional cylindrical bond with constant cross-sectional dimension to describe the connection between two adjacent voids, and the size and position of pore throat was correlated to its two neighboring pore bodies.…”