抄録
For practical use of a polymer electrolyte fuel cell (PEFC), a flooding phenomenon is one of the problems to be solved. The flooding is caused by liquid water accumulated in the gas diffusion layer (GDL) and the gas flow channels and deteriorates the performance of the PEFC. Therefore, it is necessary to clarify the gas and liquid flow in the PEFC and to control the liquid water behavior appropriately. Our research group applied the lattice Boltzmann method (LBM) for the two phase flow with high density ratio, considering the effect of wettability, and has carried out the analyses of gas and liquid water to propose optimal structures of the PEFC. Here, the LBM is a method to reproduce the macroscopic flow by considering fluid as an aggregate of a virtual particle and calculating those collisions and translation sequentially, and suitable for the two-phase flow simulation with complex boundary geometries. In this study, we simulated liquid water behavior inside of the GDL applying a low density ratio LBM with shorter computational time instead of the high density ratio model. It was confirmed that the effect of large density difference on the liquid water behavior is negligible because of the weak gas flow inside of the GDL. Using the LBM with low density ratio, we tried efficient large-scale analyses in the GDL to elucidate the effect of the GDL structure and wettability on the liquid water behavior inside of the GDL.
