陽極流道對於壓電式質子交換膜燃料電池性能之影響

Abstract

近年來由於二氧化碳排放過多造成地球暖化問題日趨嚴重，另一方面石油的價格飆漲，全球能源面臨枯竭之憂。因此尋找乾淨環保的替代能源成為各界努力的目標。以氫氣為燃料的燃料電池（Fuel Cells），具有零污染、高電能轉換效率、低噪音及可再生性等特點正符合上述需求，所以已成為為全球寄予厚望的替代能源之一。本研究是利用CFD-RC套裝軟建立一三維與暫態之模型體來模擬壓電式質子交換膜燃料電池，並探討不同的操作參數條件下其電池之效能與陰極腔體內部之流場分析。論文中分別探討燃料電池陽極端的流道設計、壓電片頻率、Membrane厚度對於壓電式質子交換膜燃料電池效能之影響。此外亦探討陰極碳板加上Nozzle及Diffuser構造對電池的表現是否有幫助，並進行一連串實驗，針對模擬結果加以驗證。經過實驗及模擬後可得到，陰極肋條比例相較於陽極流道的改變對於電池效能影響較大。本研究在模擬上最佳操作條件為Nozzle and Diffuser陰極流道設計、燃料入口溫度與電池操作溫度為323K、壓電頻率為64Hz，其電池產生的電流密度為0.376 A/cm2；在實驗上最佳操作條件為Nozzle and Diffuser陰極流道設計、燃料入口溫度與電池操作溫度為298K、壓電頻率為180Hz，其電池產生的功率為0.49Watt。

For recent years, the problem of global warming have become more and more serious. Moreover, the petroleum price has soared, reaching USD 140 per barrel. The energy depletion is approaching. People have been devoted to explore cleaner and economically efficient alternative energy resource. Meanwhile, the fuel cells which takes hydrogen as main fuel resource has been brought onto stage for the given advantage it bears including zero pollution, high energy efficiency, zero noise and vibration, and renewable. Fuel cell obviously will be one of the best green power options. Previous studies indicated piezoelectric device with proton exchange membrane fuel cells, PZT-PEMFCs, the actuating micro-diaphragm with piezoelectric effects as one of the flow channels, could be successfully operated. In this study, we discuss the performance of PZT-PEMFCs with different operating conditions, which includes anode channel design of PZT-PEMFCs, the thickness of membrane, frequency of piezoelectric device, and Nozzle and Diffuser design in cathode chamber. Rib design in cathode chamber is the most obvious factor on the performance of PZT-PEMFCs. The optimal condition in simulation is Nozzle and Diffuser design in cathode chamber, inlet gas at anode side and cell temperatures 323K, and inlet gas temperature at cathode side is 298K.The average current density when vibration frequency of piezoelectric device 64Hz in simulation is 0.376 A/cm2. The optimal condition in experiment is Nozzle and Diffuser design in cathode chamber, inlet gas and cell temperatures is 298K. The power when vibration frequency of piezoelectric device 180Hz in experiment is 0.49Watt.