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고분자전해질 연료전지의 직렬 및 병렬 출력 증가에 대한 수치해석 연구
황하나(Hana Hwang),김형만(Hyung-man Kim) 한국자동차공학회 2012 한국자동차공학회 지부 학술대회 논문집 Vol.2012 No.5-1
Proton Exchange Membrane Fuel Cell with the advantages of low-operating temperature, high current density, fast start up ability for operation becomes the most attractive power system for vehicle and power generator. It is essential for commercialization to increase the active area and power performance. PEM Fuel Cell is changed by the very complicated physical phenomenon. There is two scale-up method, both increasing active area and stacking unit cell. In the case of parallel scale-up, through the increased reaction area by increasing electrical charge current is also increased. In the case of serial scale-up, when compared with increasing active area although showed lower than the currents by stacking the unit cell voltage was increased.
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유로의 유동 방향과 높이 변화에 따른 고분자전해질 연료전지의 성능 해석
황하나(Hana Hwang),정수영(Su-young Jung),김범기(Boem-gi Kim),김형만(Hyung-man Kim),서호철(Ho-cheol Suh),박현영(Hyun-Young Park) 한국자동차공학회 2011 한국자동차공학회 지부 학술대회 논문집 Vol.2011 No.10-2
Proton exchange membrane (PEM) fuel cell has been estimated to lead future energy and researched to improve its performance and durability. In this study, we researched dependence of channel"s height and flow direction in serpentine channel flow field over numerical analysis. Flow direction affects gas concentration on the outlet of cathode side because of pressure drop. When we exchange anode and cathode side each other, water can be distributed equally over the membrane by back diffusion which partly cross over the membrane from the cathode to the anode and it makes uniformity of current density. As the results, we expect to improve the performance of PEM Fuel Cell. As channel height increases compared to the base design and the cross-sectional area increases, pressure drop is decreased and reactant gas concentration decreases. There is a trade-off between the positive parasitic power decrease and the negative electrochemical reaction decrease.
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연료전지용 메탄올 자열 개질기의 산소-메탄올 비율에 따른 성능 실험
황하나(Hana Hwang),신기수(GiSoo Shin),장상훈(Sang-Hoon Jang),최갑승(Kap-Seung Choi),김형만(Hyung-Man Kim) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.4
수소가 매력적인 연료로 각광받기 시작하면서 수요가 급증하였으며 이에 대응하여 수소 생산 기술에 대한 연구가 필요하다. 본 연구에서는 산소-메탄올 비율에 따른 연료전지용 메탄올 개질기의 반응 효율을 알아보았다. 각각의 촉매 배열에 따른 산소-메탄올의 비율(O₂/CH₃ OH)의 영향을 알아보기 위해 O₂/CH₃ OH를 0.1에서 0.4까지 0.05씩 증가시켜 반응기의 온도, 변환율, 효율에 관한 실험을 수행하였다. O₂/CH₃ OH가 0.15에서 0.2로 증가할 때 촉매층(catalyst bed)의 온도도 증가하며, 흡열 반응이 발열반응으로 변하여 반응기의 온도를 상승시켜 촉매 점화에 따라 온도는 235 ℃정도 급상승한 500 ℃가 된다. 반응기의 성능은 O₂/CH₃ OH에 크게 의존하며 이론적 연구에서 O₂/CH₃ OH는 0.23이었으나 실험 결과는 30 % 높은 0.30일 때 최적의 성능을 나타내었다. 이것은 혼합기체의 농도차이, 반응속도, 촉매, 반응기의 열손실, 반응 시 생성된 생성물 등의 변화 때문인 것으로 여겨진다. The use of Hydrogen as a fuel is receiving considerable attention and as a result, research on novel methods of hydrogen production is necessary so that the hydrogen demands in the future can be satisfied. This study presents experimental data on methanol Autothermal Reformation that quantifies the relationship between the oxygen-to-methanol ratio (O₂/CH₃OH) and reformer efficiency. For each catalyst configuration, the O₂/CH₃OH was varied from 0.1 to 0.4, with an increment of 0.05, to investigate the effects of O₂/CH₃OH on the reactor performance, including temperature profile, conversion, and efficiency. O₂/CH₃OH was increased from 0.15 to 0.20, and the catalyst bed temperature increased by 235 ℃ to approximately 550 ℃. The catalyst bed temperature increased with increasing O₂/CH₃OH as the reaction shifted from endothermic to exothermic reaction and as a result, excess heat, which raised the reactor temperature, was generated. The reactor performance was shown to be highly dependent on O₂/CH₃OH. The optimum O₂/CH₃OH = 0.30 found in the experimental tests is 30% higher than the theoretical optimum of 0.23. This is attributed to a combination of factors such as the concentrations of the O₂ and CH₃OH gas, reaction rate, catalyst effects, heat loss from the reactor, and the difference between the actual amounts of reaction products formed and the theoretical amounts of the reaction products.
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