Evaluation of hydraulic conductivity in 3D random and heterogeneous particulate materials using network model

摘要

In this study we present a three-dimensional network model for the evaluation of hydraulic conductivity using new pore structure characterization algorithms. We define a porous medium from the sphere packing generated by discrete element method (DEM). The network model is based on connectivity of pore chambers linked along discretized pathway using a harmonic mean radius value computed from a series of radius-varying tubes that represent the irregularly shaped pore channel. Particle packing cases under investigation include regular packings, monodispersed, and polydispersed cases with varying porosity. Finite element analysis is implemented to obtain hydraulic conductivity values for regular packing cases for comparison. Laboratory experimentation results corroborate numerically obtained values with good agreement. Observations show the pore space should be tessellated once pore chambers are established in order to preserve the geometrical uniqueness of randomly shaped pore channel, avoid redundancy, and minimize pore channel overlap. Also, it is observed that limits must be defined for the total number of grains needed for representativeness and discretization density for the quantification of random heterogeneous pore structure.