質子交換膜燃料電池陰極微孔網流道之三維多相流模型數值模擬與分析

Three-dimensional Multiphase Model of Proton Exchange Membrane Fuel Cell with Fine-mesh Flow Field at the Cathode Side

張嶒(Tseng Chang)

指導教授 ： 潘國隆

國立臺灣大學/工學院/機械工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202104383

摘要

近年來，具有三維結構的質子交換膜燃料電陰極微孔網流道因其在傳質和水管理方面的優點而備受關注。因此，本文以三維、多相流質子交換膜燃料電池模型針對陰極微孔網流道進行數值模擬分析，研究中使用商用軟體Fluent中的質子交換膜燃料電池模塊(PEMFC Module)進行，並透過文獻回顧選擇求解方程式與參數。另外，使用25cm2單電池治具進行性能測試實驗以驗證模型。
本研究首先將微孔網流道與常見的三蛇流道進行比較，探討了內部流場及質量傳輸機制對性能的影響。結果表明，流道中的二次流機制改善質量傳輸與水排除，能夠明顯提升PEMFC的性能輸出，實際應用操作電壓(0.7±0.05V)下，微孔網流道相較於三蛇流道電流密度最多提升達8.1%。接著，本文探討微孔網流道中幾何參數的影響，修改不同擋板角度與交錯排列之微孔網結構，討論流道中的二次流強度與渦流強度對性能輸出的影響。發現較強的二次流能夠獲得更好的性能，垂直方向對流尤為顯著。渦度強度與二次流強度具有正關係，而交錯排列之微孔網流道雖然會使渦度強度下降，但透過改變主流方向可以增強質量傳輸，得到更佳的性能輸出，在本研究之條件下，使用交錯排列與擋板角度30～40度之微孔網流道具有最佳的性能。實際應用操作電壓(0.7±0.05V)下與三蛇流道和未修改之微孔網流道相比，電流密度最多分別增加12.4%、5.6%。

關鍵字

質子交換膜燃料電池 ； 微孔網流道 ； 二次流 ； 輸出性能 ； CFD ； Fluent

並列摘要

Recently, the 3D fine-mesh flow field for proton exchange membrane fuel cell(PEMFC) cathode has attracted attention due to its advantages in mass transfer and water management. In this article, the flow pattern and cell output performance are numerically investigated by a three-dimensional, multiphase flow PEMFC model. In addition, model validation will be presented by the IV-curve test with a 25cm2 single cell.
The simulation results indicate that the fine-mesh flow field can achieve high cell output performance in comparison with the 3-serpentine flow field. The mechanism of secondary flow in the channel field and less ribs contact region are considered as the main causes for improving oxygen supply to gas diffusion layer (GDL) and better water removal. In comparison, the current density of fine-mesh increase up to 8.1% under operation voltage. Then, we discuss the influence of geometric parameters in fine-mesh flow field, including baffle angles and staggered arrangements. The results show that stronger secondary flow can achieve better performance, especially in vertical convection. Besides, the vorticity intensity has a positive relationship with the secondary flow intensity. Although the fine-mesh flow field with the staggered arrangement will reduce the vorticity intensity, the mass transport can be enhanced by changing the main flow direction and better performance output can be obtained. In this study, the modified fine-mesh flow field with staggered arrangement and a baffle angle of 30 to 40 degrees has the best performance. The current density of modified fine-mesh flow field increase up to 12.4% and 5.6% under operation voltage in comparison with 3-serpentine flow field and base case of fine-mesh flow field.

並列關鍵字

PEMFC ； CFD ； Fluent ； fine-mesh ； secondary flow ； cell performance

參考文獻

[1]L. Wang, A. Husar, T. Zhou and H. Liu, (2003), A parametric study of PEM fuel cell performance, International Journal of Hydrogen Energy. 28, 1263-1272.

[2]M. G. Santarelli, M. F. Torchio, (2006), Experimental analysis of the effects of the operating variables on the performance of a single PEMFC. Energy Conversion and Management, 48, 40-51.

[3]Tatiana J.P Freire Ernesto R Gonzalez, (2001), Effect of membrane characteristics and humidification conditions on the impedance response of polymer electrolyte fuel cells. Journal of Electroanalytical Chemistry, 03, 57-68.

[4]Bosung Kim, Dowon Cha, Yongchan Kim, (2015), The effects of air stoichiometry and air excess ratio on the transient response of a PEMFC under load change conditions. Applied Energy, 138, 143-149.

[5]Balogun O. Emmanuel, Paul Barendse, Jessica Chamier, (2018), Effect of Anode Stoichiometry and Back Pressure on the Performance of PEMFCs. 2018 IEEE PES/IAS Power Africa, 18245316.