Numerical analysis of operating conditions effects on PEMFC with anode recirculation

Abstract

We investigate different operating conditions effects, including cathode relative humidity, anode stoichiometry and inlet pressure, on PEMFC with anode recirculation by conducting dynamic simulations. The performance improvement caused by the self-humidification effect is about 6.5% with dry cathode inlet, and it is very slight with fully humidified cathode inlet. Nitrogen fraction in the anode is low in the first 20 min under a low cathode relative humidity. A 0.3–0.6 cathode relative humidity might be suitable for the simulated cases. Generally, the fuel cell benefits from increasing anode stoichiometry by enhancing the self-humidification effect, decreasing the performance decline rate and ameliorating hydrogen distribution along the channel. Increasing anode inlet pressure and cathode inlet pressure play the mitigated and exacerbated role on voltage decline, respectively. However, increasing cathode inlet pressure can significantly improve output performance especially under a low cathode relative humidity. We suggest an appropriate low cathode relative humidity, increasing anode stoichiometry, and increasing anode and cathode inlet pressure by similar amount for PEMFC with anode recirculation.