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標題: | 組裝壓力對PEMFC陰極兩相流影響計算分析 Two-dimensional modeling of two-phase transport in the cathode of a PEMFC with the influences of clamping pressure |
作者: | Chia-Hui Lin 林佳慧 |
指導教授: | 陳發林 |
關鍵字: | 組裝壓力,指叉型流,道,接觸阻抗,傳輸阻抗, clamping pressure,interdigitated channel,transport resistance, |
出版年 : | 2009 |
學位: | 碩士 |
摘要: | 本論文利用有限元素工程模擬軟體COMSOL建立二維兩相流質子交換膜燃料電池數值模型。本論文研究燃料電池陰極側輸入為空氣時,組裝壓力的不同對於氣體擴散層氧氣和液態水的分布情形。使用的模組包含應力應變模組,計算氣體擴散層經過壓縮之後的孔隙度,氧氣和液態水的擴散對流模組、質量守衡模組和動量模組。此外並分析雙極板材料為不鏽鋼時,質子交換膜燃料電池性能和氧氣和液態水飽和度的分布情形。
研究結果得知,當組裝壓力增加時,肋條下之氣體擴散層受到壓縮而變形,使得孔隙度降低,以致於影響到氣體擴散層的滲透性和擴散性,造成氧氣不易傳輸,質傳阻抗增加,導致燃料供應不足發生質傳損失,使電池性能受到影響。雖然組裝壓力的增加會減少接觸阻抗,但必須另外考慮燃料的質傳阻抗和電池性能的影響,才能找出較佳化的組裝壓力性能曲線。當雙極板材料為不鏽鋼時,由於組裝壓力較小時,接觸阻抗明顯較大,以至於歐姆阻抗相對增加,導致歐姆損失較為嚴重。因此當組裝壓力增加時,不鏽鋼的歐姆損失相對較低,使性能曲線較佳。 This study uses the finite element simulation software COMSOL project to establish two-dimensional two-phase proton exchange membrane fuel cell by numerical model. When air is input into the fuel cell cathode-side gas diffusion layer, this paper studies the distribution of generated oxygen and liquid water. Including the use of the theory of compressed gas diffusion layer of stress and strain module, oxygen and liquid water diffusive convection module, mass conservation module and momentum module, in addition to analyze the performance and the concentration distribution of the bipolar plate, which is stainless steel. Research results show that high clamping pressure will make the gas diffuser layer deformed and decrease the porosity of gas diffuser layer. The transport resistance increases with decreasing diffusion and permeability coefficients depending on the gas diffusion layer porosity. It leads to a small effective reaction area, when the saturation of liquid water is larger to study the elastic deformation of the gas diffusion layer and the mass transport of the reactants and products. It is found that there exists a better clamping force to obtain the higher power density for the proton exchange membrane fuel cell with the interdigitated gas distributors. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/43084 |
全文授權: | 有償授權 |
顯示於系所單位: | 應用力學研究所 |
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