Pressure losses in laminar flow through serpentine channels in fuel cell stacks

The pressure losses in the flow distributor plate of the fuel cell depend on the Reynolds number and geometric parameters of the small flow channels. Very little information has been published on the loss coefficients for laminar flow. This study reports a numerical simulation of laminar flow though single sharp and curved bends, 180° bends and serpentine channels of typical fuel cell configurations. The effect of the geometric parameters and Reynolds number on the flow pattern and the pressure loss characteristics is investigated. A three-regime correlation is developed for the excess bend loss coefficient as a function of Reynolds number, aspect ratios, curvature ratios and spacer lengths between the channels. These have been applied to calculate the pressure drop in typical proton-exchange membrane fuel cell configurations to bring out the interplay among the important geometric parameters.