Lattice-Boltzmann simulations of flow through NAFION polymer membranes

Simulations of flow through three-dimensional porous structures of NAFION polymer membranes are performed with a Lattice-Boltzmann method (LBM) for incompressible fluid. Geometry data of NAFION are constructed from a result of a dissipative particle dynamics simulation for three values of the water content, 10%, 20%, and 30%, and are used as the geometry input for the LBM. Permeability of the porous structure is extracted from results of the LBM simulation using Darcy's low. The permeability K is shown to be expressed as K = L² × K_tpl with a characteristic length L and the dimensionless permeability K_tpl depending only on the topological structure of the porous media. Dependence of K_tpl is examined on the pressure gradient, the fluid viscosity, and the resolution of the computational grid.