臺灣博碩士論文加值系統

本論文係利用計算流體力學軟體CFDRC建立三維質子交換膜燃料電池數值分析模型，探討不同流道配置(直通型、直通型交叉、蛇型)與其流道高寬比對燃料電池內部電、質傳現象之影響。其中，藉由不同流道高度、寬度及高寬比近似於1，探討燃料電池之內部水分排除情況，對電池性能之影響。並討論三種不同流道之最佳流道配置。
研究中可得知，在流道高度效應中，由於流道高度降低，造成流道截面積變小，使得反應氣體流速增加，並加速排除液態水，促使反應氣體抵達觸媒層參與反應，進而提升反應氣體有效使用率，延遲質傳傳輸損失之產生，並隨著流道高度縮減越大，流道截面積越小，以致於流道內部反應氣體流速增加，電池性能因而隨之提升；在流道寬度效應下，寬度較大的直通流道因流道面積增加，導致流速減緩，液態水容易累積而降低電池性能。而在直通型交叉流道和蛇型流道下，由於受到流道截面積影響，所以在寬度較小流道下，反應氣體流速較快，進而使電池性能較佳；此外，當高寬比近似於1設計中，研究中可發現流道截面積越小，電池性能越好，由於截面積縮小使得反應氣體流速增加，進而促使氣體擴散層內部液態水排除效率增強，電池性能因而隨之提升。

In this paper, three-dimensional numerical analysis models of proton exchange membrane fuel cells (PEMFCs) are established by the computational fluid dynamics software CFDRC to investigate the effects of different flow channel designs (parallel flow field, interdigitated flow field, and serpentine flow field) and flow channel aspect ratios on the electricity and mass transfer phenomena inside the PEMFCs. Different channel heights, channel widths, and channel aspect ratios approximate to 1 are used in turn to investigate the liquid water removal and the cell performance. The best design of the three types of channel designs is discussed.
For the channel height effects, the results show that a decrease of the channel height results in a decrease of the channel cross-section area. The gas velocity increases and the liquid water removal increases. The reactive gas arriving the catalyst layer for reaction increases and the mass transfer loss is delayed. As the contraction of the channel height increases, the reduction of channel cross-section area increases. Thus, the gas velocity increases and the cell performance rises. For the channel width effects, a large channel width with parallel flow field causes the gas velocity to decrease, the liquid water to accumulate, and cell performance to decrease because the channel cross-section area increases. In interdigitated flow field and serpentine flow field, the gas velocity is faster for a smaller channel width because the channel area is smaller. Thus, the cell performance is better. Besides, for channel aspect ratios approximate to 1, the results show that the cell performance is better as the channel cross-section area is smaller. As the channel cross-section area decreases, the gas velocity increases and the liquid water removal increases. Thus, the cell performance rises.

誌謝 I
摘要 II
Abstract III
目錄 V
表錄 VII
圖錄 VIII
符號說明 XIV
一、緒論 1
1.1 前言 1
1.2 文獻回顧 2
1.2.1 數值模擬 2
1.2.2 流道設計 8
1.3 研究動機 11
二、理論分析 13
2.1 模型尺寸 13
2.2 基本假設 14
2.3 統御方程式 15
2.4 邊界條件 19
三、數值方法 29
3.1 數值方法 29
3.2 格點數測試 31
3.3 文獻結果比較 32
四、結果與討論 35
4.1 流道高度效應 35
4.1.1 直通型流道設計 35
4.1.2 直通型交叉流道 38
4.1.3 蛇型流道 40
4.2 流道寬度效應 43
4.2.1 直通型流道 43
4.2.2 直通型交叉流道 45
4.2.3 蛇型流道 47
4.3 流道高寬比近似於1 50
4.3.1 直通型流道 50
4.3.2 直通型交叉流道 52
4.3.3 蛇型流道 54
五、結論與未來展望 105
5.1 結論 105
5.2 未來展望 106
參考文獻 107

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蔡瑋哲，2005，「質子交換膜燃料電池流道設計及最佳性能之研究」，華梵大學機電工程學系碩士論文,民國九十四年六月。