An innovative application of multiple impinging jet flow field in fuel cells

Abstract

AbstractThe flow field in a fuel cell is expected to distribute the reactants as uniformly as possible over the active plate, support the reasonable pressure drop across the channel and maximize the mass transfer through the catalyst layers. To simultaneously accomplish these requirements, an innovative multiple impingement jet flow field (MIJFF) is proposed in this study. A three‐dimensional thermo‐fluid simulation is used to evaluate the proposed idea and compare its performance against the commonly used parallel field flow (PFF). The domain of calculations includes a channel with multiple impingement jets linked to a porous gas diffusion layer under low Reynolds flow conditions. The results reveal that the suggested MIJFF design significantly increases the transport of the reactant gases through the catalyst layer. The penetration depth into the catalyst layer in the MIJFF arrangement is higher than that of the PFF setup and the use of the catalyst layer is optimized, which in turn can lead to a reduction of the activation drop. Compared to a PFF design under similar operating conditions, the mean Nusselt number is shown to increase by a factor of about 3.5 in the MIJFF setup. Furthermore, the temperature is more uniformly distributed in the MIJFF pattern which results in more effective distribution of the reactant gases over the active surface. The current study shows that under equal pressure drop conditions, the MIJFF exhibits a much higher performance than a PFF channel design. That is while the corresponding flow rate for the MIJFF is much lower than that of PFF.