Numerical simulation on purge strategy of proton exchange membrane fuel cell with dead-ended anode

Abstract

Proton exchange membrane fuel cells with dead-ended anode simplify fuel cell system and effectively reduce its volume, weight and cost. In this study, a three-dimensional numerical model of a dead-ended anode PEMFC with single straight channel is developed. The effect of operating conditions, including operating temperature, anode inlet pressure, and cathode relative humidity on operating characteristics of dead-ended anode PEMFC was studied in detail. What's more, the purge cycle, hydrogen utilization and energy efficiency are analyzed and the reasonable purge strategy was optimized. The results indicates that the decrease of anode partial pressure caused by the accumulation of nitrogen and liquid water is the main reason for the voltage decline during dead-ended anode operation. The purge cycle is effectively prolonged by increasing anode pressure and reducing the relative humidity of cathode. The purge cycle is extended from 437s to 562.5s as the anode pressure increased from 50 kPa to 150 kPa. The purpose of optimizing the purge strategy is to fully remove the accumulated water and nitrogen, so as to prolong the purge cycle and improve hydrogen utilization and energy efficiency. From the result, the hydrogen utilization and energy efficiency of the base case are 95.77% and 40.05%.