Prediction of Hydrophilic and Hydrophobic Characteristics of Gas Diffusion Layer on Fluid Distribution

Abstract:

The pseudo potential two-phase lattice Boltzmann method （LBM） was used to study the fluid flow state of gas diffusion layers (GDL） for carbon paper and carbon cloth under non-humidification conditions. GDL samples were constructed by random method and X-ray scanning method. In order to verify the accuracy of surface tension and contact angle calculation in the modeling process， the glass bead model was adopted. By adjusting the hydrophobic and hydrophilic characteristics of GDL， the real-time state of fluid flow in pore structure was analyzed， and the effect of hydrophobic and hydrophilic characteristics on the distribution of the water saturation in the pore structure was obtained. The results show that the water distribution in hydrophobic GDL is significantly different from that in hydrophilic GDL. Better hydrophobicity is more conducive to the discharge of water in GDL. In addition， GDL with stronger hydrophobicity significantly increases the inlet pressure of liquid water entering GDL， which may make catalyst layer （CL） more vulnerable to water penetration.

Key words:proton exchange membrane fuel cell (PEMFC）;carbon paper;carbon cloth;gas diffusion layer（GDL）;flow transport;hydrophobicity and hydrophilicity