本計畫目標為採用實驗與數值模擬方法，分析平板式固態氧化物燃料電池(Solid Oxide Fuel Cell, SOFC)之傳輸現象及其效應對電池效能之影響。針對：(1)流場均勻度對電池性能與溫度分佈之影響；(2)電極材料孔隙特性對擴散極限和輸出功率之影響；和(3)單電池較佳操作條件之測試與模擬等三大研究重點，進行深入探討。有關流場均勻度方面：我們擬利用雷射光學流場量測技術，分析影響流場均勻度的因素，如進氣端之流場特性或流道進口處之迴流特性，亦將嚐試藉由新式電池堆設計來克服密封問題。此外，我們將建立單電池性能測試平台，系統化測試不同設計單電池之輸出功率以及溫度分佈，所獲之結果對於抑制電池元件熱應力將有所助益。有關多孔電極傳輸現象分析方面：我們將建立數位質點影像測速儀與折射率契合技術，定量量測不同孔隙度之多孔介質，含以圓球陣列實驗模擬之多孔介質、常用之SOFC陶瓷材料、以及鎳網內部的傳輸機制，同時搭配以實驗數據為基礎所建立之反應流數值模式，以分析SOFC陽極與陰極之傳輸極限，進而評估減緩電池濃度極化的方法。有關操作條件較佳化測試方面：提升SOFC的燃料使用率可有助於降低發電系統的成本，故我們將藉由單電池測試或數值模擬，尋找可平衡兼顧功率密度與燃氣使用率之燃氣雷諾數的操作範圍。最後，本計畫所進行之電池性能測試，其操作條件、單電池材料與幾何形狀皆以核能研究所發展中之SOFC為參考依據，故所獲得的研究成果對於協助核研所延伸SOFC的壽命以及降低系統成本，應會有具體幫助。 ; This proposal aims to analyze transport phenomena in planar solid oxide fuel cell (SOFC) using both experimental and numerical approaches. Three key issues will be studied: (1) Effects of flow uniformity on cell performance and temperature distributions; (2) the sensitivity of porous parameters to the diffusion limitation and the power density; and (3) test and simulation of optimal operating conditions for single SOFC. For the issue of flow uniformity, non-intrusive laser optical measuring technique will be applied to analyze various flow patterns, such as the flow field in the feed header and the flow recirculation at the entrance of the flow channel. We will also attempt to propose a new stack structure for further improving the sealing problem of planar SOFC. Furthermore, a simple SOFC test platform will be established to systematically measure the current-voltage curves and temperature distributions of single cells with different degrees of flow uniformity and then study its effects on cell performance. These results should be useful for reducing the unwanted thermal stress on cell components. For the analysis of various transport phenomena in planar SOFC, velocity distributions in various porous media, including the packed bed of spheres, the commonly-used ceramics of SOFC, and Nickel mesh will be measured using digital particle image velocimetry (DPIV) and refractive index matching (RIM) technique. A 3-D reacting flow model, which will be verified by DPIV flow data and single cell testing data, will be developed to simulate complex transport phenomena in SOFC and evaluate the diffusion limitations in anode and cathode. This numerical model can be implemented in predicting the cell performance and thus further improvement of the concentration polarization for planar SOFC can be achieved. For test and simulation of the optimal operating condition, we will consider how to increase the fuel utilization rate, because the higher the fuel utilization rate is, the lower the cost of the SOFC system. Therefore, we will evaluate the optimal range of fuel Reynolds number using single cell test or numerical simulations to achieve the reasonably higher power density with economic fuel utilization. This proposal should be useful for increasing the longevity and reducing the cost of planar SOFC. ; 研究期間 9701 ~ 9712
