A numerical study of channel-to-channel flow cross-over through the gas diffusion layer in a PEM-fuel-cell flow system using a serpentine channel with a trapezoidal cross-sectional shape

A numerical study of pressure distribution and flow cross-over through the gas diffusion layer (GDL) in a PEMFC flow plate using a serpentine channel system has been undertaken for the case where the channel has a trapezoidal cross-sectional shape. The flow has been assumed to be 3-D, steady, incompressible and single-phase. The flow through the porous diffusion layer has been described using the Darcy model. The governing equations have been written in dimensionless form and solved by using the commercial CFD solver, FIDAP. The results obtained indicate that: (1) the size ratio, R, of trapezoidal cross-sectional shape has a significant effect on the flow cross-over. As R increases, the flow cross-over through GDL increases; (2) the ratio R also has a significant effect on the pressure variation in the flow field for both cross-over and no cross-over cases; (3) flow cross-over has a significant influence on the pressure variation through the channel, tending to decrease the pressure drop across the channel; (4) an increase in Re number can lead to a slight increase in the flow cross-over.