Evaluation of Two-Phase Relations

The primary drainage and steady-state flow simulations, described in the earlier section and typically devised in the petroleum/reservoir engineering applications,53 54 58,60 were deployed to evaluate the capillary pressure and relative permeability relations as functions of liquid water saturation, respectively. 

The capillary pressure response, a direct manifestation of the underlying pore morphology, can be evaluated from the two-phase LB drainage simulation and the corresponding transport relation as function of liquid water saturation can be devised as shown in Fig. 20 for the reconstructed CL micro structure.21 The overall shape of the capillary pressure curve agrees well with those reported in the literature for synthetic porous medium.55 The capillary 

Similarly, the capillary pressure - saturation relations for the reconstructed GDL structures can be constructed from the two-phase LB drainage simulations. The capillary pressure response for reconstructed non-woven GDL microstructures was also evaluated using a full morphology (FM) approach, detailed in our recent work.33 Briefly, the FM model relies on morphological decomposition of the 3-D digital image of the reconstructed GDL to 

The steady-state flow numerical experiment was primarily designed to evaluate the phasic relative permeability relations. The numerical experiment is devised within the two-phase lattice Boltzmann modeling framework for the reconstructed CL microstructure, generated using the stochastic reconstruction technique described earlier. Briefly, in the steady-state flow experiment two immiscible fluids are allowed to flow simultaneously until equilibrium is attained and the corresponding saturations, fluid flow rates and pressure gradients can be directly measured and correlated using Darcy s law, defined below. 

---