質子交換膜燃料電池堆組裝誤差對流場特性之影響

Effects of Assembly Error on Flow Field Distribution in Proton Exchange Membrane Fuel Cell Stack

林惟瑜(Wei-yu Lin)

指導教授 ： 曾重仁

國立中央大學/工學院/機械工程學系/碩士(2012年)

摘要

本研究以金屬發泡材取代傳統流道的設計作為設計基礎，探討質子交換膜燃料電池堆在組裝過程中，由於組裝應力對電池堆內元件可能造成的效應對於流場特性的影響。幾何外型使用商用繪圖軟體SOLIDWORKS繪製三維、且由十二顆單電池組成的燃料電池堆流體部分，使用CFD前處理套件Workbench內的MESH功能建構格點系統，匯入商用計算流體力學軟體FLUENT進行流場特性的數值模擬分析。以既有金屬發泡材取代傳統流道的設計，針對密封墊片侵入歧管深度、密封墊片遮蔽次流道面積、金屬發泡材滲透率的改變、以及氣體擴散層滲透率的改變，探討對電池堆流場特性的影響。
　　針對歧管尺寸，發現歧管直徑為5 mm為此流道設計下，較佳的歧管尺寸。而由本研究可知，當密封墊片侵入次流道深度比為7.5 %時，會使不均勻性指標大於10 %，且遮蔽面積愈大時，會使電池堆總壓降提升；而密封墊片遮蔽歧管深度為0.5 mm時，不均勻性指標會超過10 %，此時除了電池堆總壓降提升外，整個電池堆壓力降的主要來源則由發泡材部分，變為歧管部分影響最明顯；當電池堆中，各單電池金屬發泡材滲透率最大誤差在20 %以內時，對流場均勻性的影響不大，僅會影響電堆流量分布以及壓力降分布型態；而當氣體擴散層的滲透率最大誤差達80 %時，對電池堆均勻性以及分布型態皆無明顯影響。

關鍵字

流場 ； 密封墊片 ； 組裝 ； 金屬發泡材

並列摘要

In this study, the effects of the clamping force on flow distribution caused in the process of assembling fuel cell stack applied on components, such as gasket, are discussed. Metal foam is inserted into the flow field of proton exchange membrane fuel cell stack to replace the traditional design. A three-dimensional geometry is built by using SOLIDWORKS and established the mesh system in ANSYS Workbench. Finally, the discrete equations are solved by the CFD software FLUENT version 13.0.
　For the present flow field design, uniformity index could be maintained below 10 % if the manifold diameter is larger than 5 mm. When the gasket intrusion depth in channel is larger than 7.5 %, the uniformity index would exceed 10 %. The pressure drop in each cell would increase as the gasket intrusion depth in channel increases. On the other hand, the gasket intrusion depth in manifold will cause the uniformity index exceed 10 % over 0.5 mm and the pressure drop in manifold dominates the total pressure drop instead of metal foam. When the largest difference of permeability of metal foam between each cell is under 20 %, permeability of metal foam would not affect uniformity obviously but only the distribution. In gas diffusion layer, the permeability would not affect the uniformity and distribution greatly even if the largest difference of permeability reaches 80 %.

並列關鍵字

flow field ； gasket ； assembly ； metal foam

參考文獻

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