摘要
本研究主要是改善蛇型流道末端的氣體濃度不足的問題。因此將流道縮短並設計成改良式流道(一)及改良式流道(二)。改良式流道(一)和改良式流道(二)是將原流道縮短1/2及1/4。藉由實驗獲得平行流道、蛇型流道、改良式流道(一)及改良式流道(二)燃料電池的性能。透過模擬觀察燃料電池內部的電流密度分佈、水的飽和度分佈、溫度分佈及壓力分佈等；並比較燃料電池在不同流道下的差異結果。輸出功率是改良式流道(一) 33.5W最大，其次是蛇型流道33.36W，改良式流道（二）25.26W為第三，第四為平行流道24.53W。電流密度是改良式流道(一) 6930 A/m2最高，其次是蛇型流道6647 A/m2，改良式流道(二) 6251 A/m2為第三，第四為平行流道5549 A/m2。進出口壓力差是改良式流道(一) 1769 N/m2最大，其次市蛇型流道1724 N/m2，改良式流道(二) 800 N/m2為第三，第四為平行流道735 N/m2。改良式流道(一)的輸出功率及電流密度都優於蛇型流道，有明顯的改善蛇型流道在流道末端氣體濃度不足的問題。相對的進出口的壓力差也比較高。改良式流道(二)的輸出功率及電流密度都低於蛇型流道，但在進出口壓力差只有蛇型流道的一半。不論是蛇型流道、改良式流道(一)及改良式流道(二)的燃料電池性能結果都優於平行流道的燃料電池。

Abstract
The aim of this study is to improve the problem of insufficient gas concentrations at the end of channel with the serpentine flow channel design. By using the idea of combining the parallel and the serpentine channel patterns, two new channel patterns, namely, improved channel (1) and improved channel (2), are proposed. The improved channel (1) and the improved channel (2) are built by shortening original serpentine channel by 1/2 and 1/4 of length, and in the mean time introducing the feature of the parallel channels. Experiments of the performance of the fuel cell with the parallel channel, the serpentine channel, the improved channel (1) and the improved channel (2) are conducted. Meanwhile, numerical simulation of the internal distributions of current density, water saturation, temperature, and pressure are carried out. Comparison between the experimental and numerical data under different conditions are performed. It is found that the output power with the improved channel (1) is 33.5W in maximum, followed by the serpentine channel 33.36W, the improved channel (2) 25.26W,and the parallel channel 24.53W. The current density reached by the improved channel (1), the serpentine channel, the improved (2), and the parallel flow channel are 6930,6647,6251, and 5549 A/m2, respectively. In addition, the pressure drop from the inlet to the exit of the fuel cell is 1796 N/m2 for improved channel (1), 1724N/m2 for serpentine channel, 800N/m2 for improved channel (2), and 735N/m2 for the parallel channel. The output power and current density of improved channel (1) are higher than those of the serpentine channel; however, the improved channel (2) is worse that the serpentine channel in terms of the output power and current density. Nevertheless, the improved channel (2) can lead to a very small pressure drop.

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