本文提出以三維之新型螺旋流道做為燃料電池的流道模型，並以數值模擬及實驗進行研究驗證。蓋因當前燃料電池的流道設計多以矩形流道為主，諸如平行、蛇行或指叉形等，具有直角轉彎阻抗太大的缺失，而相較於直管，彎管中產生之二次流可確實增進熱傳與質傳等效應。又矩形外型之燃料電池需多螺絲的鎖固方式，也有應力分佈不均勻以及組裝鎖緊困難之處。因此，本研究設計一外型為圓形並由五條流道組成之螺旋形流道，先以順時針方向流入中心，再以逆時針方向由中心流出，總反應面積為25cm2。
經由數值模擬，螺旋彎管可持續的維持或甚至增強二次流之產生；又入出口流道為間隔方式排列，導致兩流道間產生極大的壓降，以上設計皆加強了燃料的擴散效率。平滑的流道亦減少了壓阻的影響。而出口流道寬度縮減的設計，使得燃料即使在幾乎被消耗完的出口流道中，還能維持其流動速度，更有助於燃料的輸送與排水效率。於實驗部分，圓柱結構燃料電池透過壓應力測試證實可得到較均勻的應力場分佈，而圓柱外型上下端板直接迫緊的鎖固方式，亦有助於提升組裝過程中的方便性以及安全性。由以上之改良設計，與現有常用之蛇行流道相比，螺旋形流道燃料電池之性能提昇有12%之多，模擬與實驗間的誤差約在10%以內，兩者結果堪稱吻合。
此外，針對螺旋流道流場部分，本研究以簡易共軛梯度法建立最佳化運算系統，利用最佳化方法找出最佳化參數，改善螺旋流道入口流量分配不甚均勻的問題，使燃料電池之性能表現約提升6%。由以上之研究，螺旋流道確實為增進質子交換膜燃料電池的良好設計。

A three - dimensional model of proton exchange membrane fuel cell
(PEMFC) with special design of spiral channels is developed experimentally and numerically in this research. Due to the secondary vortices effect which can enhance heat and mass transfer in curved pipes, spiral channel patterns are used here to improve on the geometry of present fuel cell models. The spiral channels are built with five inlet and outlet channels, the overall reaction area is 2500 mm2. Through the simulation results, the flow direction of spiral channels can maintain or even strengthen secondary flow and improve the mass transfer in PEMFC. The smooth channels can widely decrease the drag force and enhance the efficiency of PEMFC. Comparing with inlet channels, the contraction design of outlet channel widths can prevent from a great quantity of water flooding. According to the above statements, it is found that the current densities of spiral channel PEMFC are 12.5% higher than serpentine channel PEMFC. In addition, the numerical predictions were reasonably in agreement with the experimental results. The errors between numerical and experimental results are 6.7-8.1%. The result reveals that the spiral design of this paper is a useful design to enhance the efficiency of PEMFC. In addition, the simplified conjugate - gradient method (SCGM) has been applied to optimize the uniformity of flow filed which can be one of methods to improve the efficiency of fuel cell. The five channel widths of spiral channel are optimized through SCGM to uniformize the flow field. The result reveals that the current densities of PEMFC through optimal search are 5.1%-7.3% higher than original ones.

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