Evaluation of the Darcy's law performance for two-fluid flow hydrodynamicsin a particle debris bed using a lattice-Boltzmann model

In the present paper, multiphase flow dynamics in a porous medium are analy zed by employing the lattice-Boltzmann modeling approach. A two-dimensional formulation of a lattice-Boltzmann model, using a D2Q9 sc heme, is used. Results of the FlowLab code simulation for single phase flow in porous media and for two-phase flow in a channel are compared with anal ytical solutions. Excellent agreement is obtained. Additionally, fluid-flui d interaction and fluid-solid interaction (wettability) are modeled and exa mined. Calculations are performed to simulate two-fluid dynamics in porous media, in a wide range of physical parameters of porous media and flowing fluids. It is shown that the model is capable of determining the minimum body force needed for the nonwetting fluid to percolate through the porous medium. De pendence of the force on the pore size, and geometry, as well as on the sat uration of the nonwetting fluid is predicted by the model. In these simulat ions, the results obtained for the relative permeability coefficients indic ate the validity of the reciprocity for the two coupling terms in the modif ied Darcy's law equations. Implication of the simulation results on two-flu id flow hydrodynamics in a decay-heated particle debris bed is discussed.