• 한국수소및신에너지학회논문집
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• 제10권2호
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• pp.107-118
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• 1999

MCFC 발전 기술의 실용화를 위하여 $3,000cm^2$ 면적의 단위전지 20장으로 구성된 5 kW 급 MCFC 스택을 5,760 시간 동안 운전하여 그 운전특성을 파악하였다. 스택은 7.6 kW의 출력을 보여주어 설계치보다 높은 출력을 보여주었다. 아울러 스택 성능 및 스택내 운전온도 분포변화를 해석하기 위하여 열전달, 유동방정식 및 연료전지 반응특성을 고려한 수학적 모델을 완성하였다. 완성된 수학적 모델 전산 모사를 위하여 상용 CFD 코드를 이용한 프로그램을 개발하였고 개발된 스택 전산모사 코드는 실제 운전된 5 kW MCFC 스택 운전 자료와 이론적 계산결과와 비교하여 그 신뢰성을 확인하였다.

• 대한기계학회논문집B
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• 제41권2호
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• pp.109-115
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• 2017

전산유체해석(CFD) 기법을 이용하여 음극 지지체형 고체산화물 연료전지(SOFC)에 대한 수치해석을 수행하였다. 평판형 구조의 SOFC 에서 가스채널과 리브폭 변화에 따른 성능과 온도균일성에 관한 연구가 이루어졌다. 전산해석 툴로서는 공개소스 전산유체해석 툴박스인 OpenFOAM 을 이용하였다. 수치해석결과, 산소고갈이 일어나지 않는 범위 내에서 가스채널과 리브폭의 증가는 성능과 온도 균일성에 크게 영향을 미치지 않음을 알 수 있었다. 하지만 넓은 리브폭의 사용과 고전류밀도에서의 작동은 산소고갈로 인한 성능저하의 가능성이 있음을 확인하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 춘계학술대회논문집
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• pp.159-164
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• 2009

The water droplet motion and the interaction between the droplets in a PEMFC air flow channel with multiple pores, through which water emerges, is studied numerically by solving the equations governing the conservation of mass and momentum. The liquid-gas interface is tracked by a level set method which is based on a sharp-interface representation for accurately imposing the matching conditions at the interface. The method is modified to implement the contact angle conditions on the walls and pores. The dynamic interaction between the droplets growing on multiple pores while keeping the total water flow rate through pores constant is investigated by conducting the computations until the droplet motion exhibits a periodic pattern. The numerical results show that the droplet merging caused by increasing the number of pores is not effective for water removal and that the contact angle of channel wall strongly affects water management in the PEMFC air flow channel.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2390-2395
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• 2008

The water droplet motion in an air flow microchannel with pores through which water emerges is studied numerically by solving the equations governing the conservation of mass and momentum. The gas-liquid interface is tracked by a level set method which is based on a sharp-interface representation for accurately imposing the matching conditions at the interface and is modified to implement the contact angle conditions on the wall and pores. The numerical results show that the droplet growth and detachment pattern depend significantly on the contact angle and inlet air velocity. Also, the dynamic interaction between the droplets growing on multiple pores is investigated. The pore arrangement subject to droplet merging is found to be not effective for water removal.

• Korean Chemical Engineering Research
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• 제54권6호
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• pp.847-853
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• 2016

본 연구에서는 3차원 전산유체역학 모델을 적용하여 서펜타인 유로를 갖는 고분자 전해질 분리막(PEM) 연료전지의 성능평가를 수행하였다. PEM 연료전지의 전산 모델은 등온조건하에서의 이동현상을 고려하여, 물질 및 운동량 전달, 전극에서의 반응속도론 그리고 전기적 흐름을 모두 포함하였다. 한편, 병류로 흐르도록 형성된 구조의 유로 형태는 본 연료전지모델에서 유로의 폭과 높이의 비인 종횡비와 유로와 립 폭의 비인 반응면적비를 변화시키며 다양한 형상으로 고려되었다. 유로의 형상이 변화될 경우 연료전지 내부의 수소와 산소의 질량분율 분포가 계산되었으며, 이에 따라, 활성화과전압의 계산 값이 변하게 되며 전류밀도 분포가 최종적으로 결정되었다. CFD 결과는 종횡비가 클수록 성능이 증가하고 반응면적비가 클수록 성능이 감소하는 것을 보였다. 본 연구의 모델에 의하면 서펜타인 유로의 형상에 의해, 성능특성이 경향성을 보이는 결과를 보여주었으며, 이와같은 결과는 다른 문헌에 보고 된 CFD 결과들과 전반적으로 잘 부합하는 것으로 나타났다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3114-3119
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• 2008

Relatively high convective flow exists in the under-rib regions of a gas diffusion layer (GDL) when serpentine flow fields are employed in a PEMFC. This under-rib convection is believed to be favorable for the performance of PEMFCs, by enabling more effective use of catalysts in the under-rib regions. From the fact that the under-rib convection in a GDL is directly proportional to the permeability of the GDL, computational fluid dynamics (CFD) simulations were performed to discover the relationship between the GDL permeability and the PEMFC performance. Single-, triple-, and quintuple-path parallel serpentine flow fields for $9\;cm^2$ active cell area were considered while changing the GDL permeability from $1{\times}10^{-12}$ to $5{\times}10^{-11}m^2$. The results showed that higher GDL permeability generally resulted in better performance of PEMFCs, but the degree of performance enhancement became smaller as the parallel path number increased. The effects of the permeability on the local variables were also discussed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2828-2833
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• 2008

Water management is one of many operating parameters, which influences the performance and stability of a proton exchange membrane fuel cell (PEMFC). Local humidity condition including liquid water saturation has profound impacts on the distributions of overpotentials, current density, and membrane water content. Computational fluid dynamics simulations were conducted to investigate the effect of the inlet humidity variation on the performance of a PEMFC of $9\;cm^2$ active cell area with serpentine flow fields. The results showed that the performance of the simulated PEMFC remained at an almost same level when the cathode inlet humidity was changed from 100% to 60%, while reaching its maximum at air humidity of 80%. However, further decrease in the cathode inlet humidity below 40% started to significantly deteriorate the performance of the PEMFC. The variations of overpotentials, membrane water content, etc. due to the change in the cathode inlet humidity were also discussed.

• 한국태양에너지학회 논문집
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• 제32권spc3호
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• pp.275-281
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• 2012

Proton Exchange Membrane Fuel Cells (PEMFC) are the most appropriate for energy source of small robot applications. PEMFC has superior in power density and thermodynamic efficiency as compared with the Direct Methaol Fuel Cell (DMFC). Furthermore, PEMFC has lighter weight and smaller size than DMFC which are very important factors as small robot power system. The most significant factor of mobile robots is weight which relates closely with energy consumption and robot operation. This research tried to find optimum specifications in terms of type, number of cell, active area, cooling method, weight, and size. In order to find optimum 500W PEMFC, six options are designed in this paper and studied to reduce total stack weight by applying new materials and design innovations. However, still remaining problems are thermal management, robot space for energy sources, and soon. For a thermal management, design options need to analysis of Computational Fluid Dynamics (CFD) for determining which option has the improved performance and durability.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.211-216
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• 2012

Proton Exchange Membrane Fuel Cells (PEMFC) are the most appropriate for energy source of small robot applications. PEMFC has superior in power density and thermodynamic efficiency as compared with the Direct Methaol Fuel Cell (DMFC). Furthermore, PEMFC has lighter weight and smaller size than DMFC which are very important factors as small robot power system. The most significant factor of mobile robots is weight which relates closely with energy consumption and robot operation. This research tried to find optimum specifications in terms of type, number of cell, active area, cooling method, weight, and size. In order to find optimum 500W PEMFC, six options are designed in this paper and studied to reduce total stack weight by applying new materials and design innovations. However, still remaining problems are thermal management, robot space for energy sources, and so on. For a thermal management, design options need to analysis of Computational Fluid Dynamics (CFD) for determining which option has the improved performance and durability.

• 한국소음진동공학회논문집
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• 제18권10호
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• pp.1073-1081
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• 2008

A centrifugal turbo blower of the fuel cell electric vehicle (FCEV) operates at very high speed above 30000 rpm in order to increase the pressure of the air, which supplied to a stack of FCEV, using rotation of its impeller blades. Vibration which originated from the blower is generated by unbalance of mechanical components, rotation of bearings and rotating asymmetry that rotate at high speed. The vibration is transmitted to receiving structure through vibration isolators and it can causes serious problems in the noise, vibration and harshness(NVH) performance. Thus, the study about reducing this kind of vibration is an important task. In this paper, dynamic analysis of the blower executed by numerical simulation and experimental analysis of the blower is also performed. Then, measured and simulated results are compared in order to validate of the simulation. Finally, reducing vibration through modifying mount stiffness is the main purpose of this paper.