Modeling fluid flow in fuel cells using the lattice-Boltzmann approach

Two flow problems relevant to fuel cell modeling are simulated with the lattice-Boltzmann (LB) approach. The first is a 3D viscous flow through a section of serpentine channel and the second is a 2D channel filled or partially filled with porous medium. In the first case, attention is given to the implementation details such as inlet–outlet boundary conditions, nonuniform grid, and forcing. It was shown that the flow pattern and pressure distribution depends sensitively on the flow Reynolds number as the flow Reynolds number is increased from 10 to 1000. There also appears to be some evidence that the transition to a turbulent flow occurs at Reynolds number on the order of 1000. In the second case, the effects of multiple time scales and interface between the porous medium and clear channel are considered. It was shown that, in order to obtain correct results at the interface or near the boundary, the physical time scales of the problem must be kept larger than the lattice time. This can be achieved by using a small particle velocity in the LB scheme.