Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1291520 | Journal of Power Sources | 2008 | 11 Pages |
Two-phase flow dominated by capillary effects in model fibrous media is studied combining pore-network simulations and visualisations on transparent micromodels. It is shown that the process of liquid water invasion in a hydrophobic medium can be simulated using the classical invasion percolation algorithm provided that the contact angle (measured in air, which is the wetting phase) is sufficiently far below 90°. For contact angles approaching 90°, changes in the interface local growth mechanisms lead to changes in the invasion pattern.Then it is shown that the invasion pattern is dramatically different in a hydrophilic medium. Impact of wettability (hydrophobic vs. hydrophilic) on evaporation pattern is also analysed.In a last part, implications of the study findings on the water management problem in the gas diffusion layers (GDLs) of PEMFC are discussed. Our results provide pore-scale explanations to the advantages of hydrophobic GDLs.