| 摘要: | 燃料電池是一種潔淨且高效率的能源轉換裝置，以燃料電池當作能源的載具，能有效提高能源的使用率和大大減少在使用端之環境汙染問題。在目前多種不同電解質之燃料電池中，固態氧化物燃料電池(Solid Oxide Fuel Cell, SOFC)具有最高操作溫度，可高達700 ~ 1000℃，故可提供較高功率之電力輸出，且其廢熱可被循環再利用，是目前被看好最具發展潛力，可用於作發電裝置之燃料電池。 如何降低不可逆的極化與改善劣化現象對電池發電效率之影響，是目前發展SOFC所急需突破的關鍵技術之ㄧ。而雙極板(bipolar plates or interconnects)流道之最佳化設計，攸關流場分佈的均勻度，是均衡電極之電化學反應的條件之ㄧ，進而才能有效地抑制濃度極化(concentration polarization)，故為本研究之重點。此外，解析SOFC內部之傳輸現象，有助於了解劣化產生的機制，為本研究另一重點。實際SOFC的高溫操作條件並不適合流場觀測，因此有關流場特性之相關研究，目前僅有數值分析，實驗模擬量測結果則幾無。是故，本計畫擬結合實驗模擬和數值分析，探討SOFC內部傳輸現象，整合非侵入式雷射光學量測技術，以建構一量測電池元件性能特性參數之診斷平台，提供SOFC電池元件最佳化設計所需之基本參數的數據分析。SOFC內部之傳輸現象相當複雜，含動量和能量傳輸(momentum and energy transport)、氣體燃料通過多孔介質(porous media)之質量擴散機制(mass diffusion)和電化學反應(electrochemical reactions)等。本計畫將利用雷射誘導螢光法(LIF)研究流體於雙極板流道內之流動狀態，並利用數位質點影像測速技術(DPIV)，進行流場特性參數之定量量測，進而建立完整的數據資料庫，含流場觀測影像、速度場、渦度場等。數值模擬方面，擬採用我們已相當熟悉之CFD-RC計算流體力學軟體，計算可與實驗結果相互驗證的熱流特性參數，同時鏈接化學反應模擬軟體，探討熱流特性參數對電化學反應造成之影響。此測試平台的建立，有助於平板式SOFC電池元件性能評估和預測，所得結果可作為改善平板式SOFC雙極板設計及其最佳化之重要參考依據。 Fuel cell is a clean and efficient energy transform device. It is a suitable energy carrier because of its ability to mitigate the energy shortage problem and to meet the international requirement for reduced green house gases. Among many types of fuel cells, solid oxide fuel cell (SOFC) has the most promising potential for power generation due to its higher electric output and reusable high-temperature waste heat. How to reduce the polarization and improve the degradation that influence cell performances profoundly are one of the key technologies needed to be breakthrough in SOFC？HH？HHs R&D. The optimal channel design of the interconnects for the planar SOFC is to provide a uniform flow distribution, which is important for the balance of electrochemical reactions in electrolytes to inhibite the concentration polarization, as the first object of this proposal. Furthermore, analyses of transport phenomena in SOFC are important for the understanding of the degradation mechanism, and this is the second object. However, the actual high-temperature operating conditions of SOFC have limited a direct visualization and measurement of the flow field to be applied in interconnects, so far as present only numerical studies are available in this topic. Thus, this proposal aims to estimate the correlation with multi transport phenomena in SOFC and to establish a reliable platform for testing the performance of the components in planar SOFC. The testing platform consists of non-intrusive optical measurements and numerical simulations that make optimization of the cell components possible. The transport phenomena in SOFC are very complex, including the momentum and energy transport, the mass diffusion via porous media, and electrochemical reactions. We will investigate the flow field in channels of the interconnects using laser induced fluorescence technique (LIF). In addition, measurements of characteristic parameters of the flow field using the digital particle image velocimetry (DPIV) will be carried out. Hence, the database such as the images of flow visualization, the velocity field and the vorticity field can be obtained. For numerical simulations, we will apply CFD-RC software which will be coupled with some chemical softwares (e.q. CHEMKIN) to estimate the influence of electrochemical reactions. This proposed essential, as an important designed criterion, for optimization of the interconnects of the planar SOFC. The testing platform will simulate the cell performance of planar SOFC, and the data obtained play an important role for both optimal channel design in interconnects and understanding of the degradation mechanism. 研究期間：9501 ~ 9512 |
