Performance evaluation of a blocked regulated lateral release channel for proton exchange membrane fuel cell based on entropy generation analysis

Abstract

Oxygen-deficient regions at low voltage restrict the enhancement of proton exchange membrane fuel cell performance. To address this issue, a blocked regulated lateral release channel (BRLRC) is proposed to divert oxygen from blocked channel into oxygen-deficient areas. The implications of BRLRC on oxygen distribution, drainage capacity and output performance are investigated by adopting a three-dimensional multi-phase model. Through entropy generation analysis, multiple irreversible losses across varying locations for various flow fields are assessed. Structural optimization of BRLRC, focusing on parameters such as width, entrance, and junction positions of auxiliary channels, is conducted to boost net output power of the fuel cell. Results show that compared to the blocked channel, BRLRC further augments the output power, oxygen uniformity, drainage capacity and diminishes pump power. Analysis of cathodic entropy generation reveals that over 90% stems from mass transfer, with the catalyst layer as the main contributor, while BRLRC significantly reduces total entropy generation by mitigating mass transfer irreversibility. By accurately oxygen allocation, the structurally optimized BRLRC attains peak output power even with an oxygen concentration that is 7.5% lower than the maximal observed concentration. Building on this efficiency, when contrasted with the straight channel, BRLRC amplifies the maximum net output power by 9.04%, exceeding the 5.18% increase achieved by the conventional blocked channel.