Full Coverage of Two-Phase Transports in a Porous Electrode of a PEM Fuel Cell

質子交換膜燃料電池多孔電極之兩相輸送機制之全面相探討

黃鎮江(Jenn-Jiang Hwang)

《中國機械工程學刊》 29卷3期 (2008/06) Pp. 195-205

https://doi.org/10.29979/JCSME.200806.0002

摘要

本文提出了一個嶄新的質子交換膜燃料電池多孔電極的非等溫兩相模型，首度成功地將兩相流體、兩相溫度（熱）、以及兩相電流於耦合單一模型中。在多孔電極熱傳部分，本文採用了局部非熱平衡模型同時分析多孔電極的固相與氣相溫度，熱源包含了電化學反應的不可逆熱、歐姆電阻產生的焦耳熱、以及水凝結/蒸發潛熱等；兩相流體部分則同時分析氣體和液體的速度場並同時探討液氣界面的毛細作用力；至於兩相電流部分則成功地分離出電子導體內的電子流與流經Nafion®的質子流。參數研究包括陰極進氣的相對濕度與雙極肋板之溫度，結果顯示增加了在肋雙極肋板溫度可以減少反應氣體的飽和度、降低水凝結可能性。
藉由本模型之建構與分析已完整地並詳細多孔電極之兩相輸送機制。

關鍵字

質子交換膜燃料電池 ； 模型 ； 兩相輸送

並列摘要

A non-isothermal two-phase model fully coupling fluid flow, heat transfer, and electrochemical processes is developed to inspect two-phase transports in a porous cathode of a proton exchange membrane (PEM) fuel cell. A local thermal non-equilibrium model accounting for irreversible heat due to electrochemical reactions, Joule heating arising from Ohmic resistance, and latent heat of water condensation/evaporation was employed to describe two-phase temperature in the porous cathode. Separate velocity fields of gas and liquid phases are solved simultaneously to illustrate the two-phase flow in a porous cathode. Parametric studies included the relative humidity of cathode feeding the rib-shoulder temperature. Detailed characteristics about two-phase transports in a porous cathode have been presented and discussed in detail, such as liquid/vapor velocities, phase-change mass transfer rate, water saturation, and relative humidity. Results of the capillary pressure and gaseous flow show that an increase in the rib shoulder temperature can reduce the level of liquid saturation.

並列關鍵字

PEM fuel cell ； Model ； Two-phase transports