本論文旨在利用計算流體力學軟體CFD-RC建立三維質子交換膜燃料電池數值模型，與反算最佳化程式的結合，針對直通式反應氣體流道，作一最佳流道形狀設計。論文中流道的流形狀參數，主要是透過雲形線（B-Spline）此副程式作修正，並利用反算方法中的拉凡格式法來做最佳化設計，藉由設計不同的電流密度，得到不同的流道形狀。
吾人分別針對（i）Case A：在全長60％、（ii）Case B：全長70％及（iii）Case C：全長80％處開始作流道最佳化設計，且操作電壓則分別對電壓V=0.7及電壓V=0.4 兩部份作討論。設計之目標為希望尾端設計流道正上方之電流密度增加為原始的20個百分比與30個百分比。
根據吾人觀察，設計出來的流道，並非一個規則的形狀，而是呈現一個往下縮後又往上長的曲線。因為在作最佳化設計時，一開始修正過大，超過了設計目標，程式為了要滿足收斂條件而自我修正，因此有此一形狀產生。
最後探討各個流道的性能比較，如電流密度、液態水問題及壓力分佈等。結果發現，經過設計後的流道，其電流密度確實有增加，液態水的堆積問題也有減少，的確有提升其性能。

In this thesis, the CFD (Computational Fluid Dynamics) software that is named CFD-RC is used to set up a three-dimensional numerical model of the straight proton exchange membrane fuel cell (PEMFC), and combine with the Levenberg-Marquardt Method which is one of the technique of Inverse Design Problem for optimizing the shape of gas channel at cathode side in the PEMFC. About the geometry of the redesign gas channel is generated by using B-spline curve method which enab les the shape of the fuel channel to be completely specified using only a small number of control poi nts, the technique of parameter estimation for inverse design problem is thus chosen.
In the studying, I separate three difference example :(i) Case A: In total length 60%, (ii) Case B: Total length 70% and (iii) Case C: 80% of total length to do optimal design, the operation voltage is V=0.7 and V=0.4, respectively. And I hope the program can reach the goal the current densities located on carbon plate near the outlet of channel at cathode are gained 20% or 30%.
According to observe, the channel shape is not regular, it is curve which has frank style turning downward and upward. Because of while doing the optimal design, it is too much to modify at the beginning, and having exceeded the design object. In order to be satisfied the object function, the program is revised by itself, so getting this special shape.
Finally, I discuss and compare flow performance, electric current density, liquid water issue and pressure distribute etc. Results show that by utilizing the redesigned optimal gas channel, the total current of PEMFC can be increased, and at the same time the phenomena for saturated water accumulation in the channel can be greatly reduced.

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