• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2157-2162
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• 2004

As the friction between two mated materials generates electrostatic voltage, vehicles especially in the cold climate has been accumulated an electrostatic voltage by the reason of fuel flow in the fuel line, air flows out side of vehicle, etc. In this study, investigations of electrostatic discharge characteristics has been carried out in the fuel systems of gasoline engines depending on the environment temperature. For the experiment, conventional fuel filters(paint coated steel case) and specially made testing equipment are prepared. The experimental results shows, an accumulation speed of electrostatic voltage depends on the environmental temperature and new methods of testing procedures are required compare to SAE standards.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.1992-1996
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• 2007

This study focuses on the hydrogen embrittlement of iron tube for fuel line of PEMFC (Proton Exchange Membrane Fuel Cell). PEMFC is operated by feed of hydrogen as a reactant and steam for proton conductivity of membrane. However, the environment with hydrogen and steam occur the hydrogen-induced degradation in BOP system. When iron tube was exposed to hydrogen and steam condition for 24 hours, the oxide layer on the surface was decreased by reduction. When the ambient temperature was 90$^{\circ}C$ micro cracks were found on the surface than any other temperature. The mechanical strength of iron tube was 3% lower than that of non-experiment tube. Maximum tensile stress was decreased 8%.

• Journal of the Korean Ceramic Society
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• v.53 no.1
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• pp.122-127
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• 2016

Tin oxide ($SnO_2$) nanoparticles have been synthesized by solution combustion method using citric acid as a fuel. The oxide to fuel ratio has been varied to obtain ultrafine nanoparticles with better surface area; such particles will be useful in many applications. With this synthesis method, spherical particles are formed having a particle size in the range of 11-30 nm and BET surface area of ~ $24m^2/g$. The degree of agglomeration of $SnO_2$ nanoparticles has been calculated.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.8 s.227
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• pp.929-936
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• 2004

In the present work, shape of the mixing vane in Plus7 fuel assembly has been optimized numerically using three-dimensional Reynolds-averaged Navier-Stokes analysis of flow and heat transfer. Standard $k-{\epsilon}$ model is used as a turbulence closure. The Response surface method is employed as an optimization technique. The objective function is defined as a combination of heat transfer rate and inverse of friction loss. Bend angle and base length of mixing vane are selected as design variables. Thermal-hydraulic performances for different shapes of mixing vane have been discussed, and optimum shape has been obtained as a function of weighting factor in the objective function.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.208-211
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• 2007

Polymer Electrolyte Membrane fuel cell(PEMFC)의 촉매로는 주로 carbon을 지지체로 사용한 Pt/C 흑은 Pt alloy/C을 사용하게 된다. 이때 PEMFC의 상용화에 있어 촉매의 안정성은 상용화 실현에 있어 중요한 요인으로 인식되고 있다. 촉매의 성능 저하는 Pt의 활성 면적(Active surface area)의 감소가 원인으로 얘기되어 지고 있으며 이는 지지체로 사용한 탄소에 나노 크기로 분산되어 있던 Pt 입자가 커지면서 활성 면적이 감소되어 지기 때문이다. 이번 연구에서는 상용 Pt/C를 사용하여 Cyclic Voltammetry(CV)의 장기간 운전 및 다양한 조건 변화를 통하여 Pt입자의 크기 증가에 미치는 요인에 대한 연구를 진행하였다. 이와 더불어 Linear Sweep Voltammety(LSV), TEM, 등을 통한 분석이 진행되었다.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3649-3653
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• 2013

As anode fabrication with different materials has been proven to be a successful alternative for enhancing power generation in the microbial fuel cells, a new approach to improved performance of MFCs with the use of menadione/carbon powder composite-modified carbon cloth anode has been explored in this study. Menadione has formal potential to easily accept electrons from the outer membrane cytochromes of electroactive bacteria that can directly interact with the solid surface. Surface bound menadione was able to maintain an electrical wiring with the trans-membrane electron transfer pathways to facilitate extracellular electron transfer to the electrode. In a single chamber air cathode MFC inoculated with aerobic sludge, maximum power density of $1250{\pm}35mWm^{-2}$ was achieved, which was 25% higher than that of an unmodified anode. The observed high power density and improved coulomb efficiency of 61% were ascribed to the efficient electron shuttling via the immobilized menadione.

• Transactions of Materials Processing
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• v.15 no.3 s.84
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• pp.226-231
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• 2006

The fuel injector is a pa.1 that controls the fuel supply of automotive engine. The housing of the fuel injector supports the rod, the needle valve and the solenoid. In this study, the rigid-plastic FE-analysis by using the design of experiments (DOE) and the response surface methodology (RSM) has been performed to produce the product reducing the under-fill and the maximum effective strain. From the results of DOE, the stem of counter punch and the face angle of punch at the $1^{st}$ process, and the stem of punch at the $2^{nd}$ process were determined as the significant design variables far each response such as the upper under-fill, lower under-fill and the maximum effective strain. From the results of RSM, the optimal values of the design variables have been also determined by simultaneously considering the responses.

• Journal of the Korean Ceramic Society
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• v.36 no.4
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• pp.360-365
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• 1999

The combustion process was applied to synthesize the LiAlO2 powder with high specific surface area and pure crystalline ${\gamma}$-phase. For the combustion synthesis of LiAlO2 which is a binary-component oxide in-cluding lithium and aluminum ions the mixture of citric acid and urea with stoichiometric composition was selected as a promising fuel. The highest combustion temperature was measured in the reaction using the mixed fuel with a stoichiometric composition. The synthesized powder was very fine and its specific surface area was more than 15 m2/g.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3140-3141
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• 2008

The output power efficiency of the fuel cell system depends on the demanded current, stack temperature, air excess ratio, hydrogen excess ratio and inlet air humidity. Thus, it is necessary to determine the optimal operation condition for maximum power efficiency. In this paper, we developed a dynamic model of fuel cell system which contains mass flow model, diffusivity gas layer model, membrane hydration and electrochemistry model. In order to determine the maximum output power and minimum use of hydrogen in a certain power condition, response surface methodology (RSM) optimization based on the proposed PEMFC stack model is presented. The results provide an effective method to optimize the operation condition under varied situations.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.500-502
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• 2008

In generally, a high pressure fuel injection pipe has been often used as a fuel supply line in automobiles or other diesel engines. Such conventional high pressure fuel injection pipe, however, has suffered from the problem that is folding and hair cracks created therein. The defects can be locally formed in the inner wall surface of the pipe at the connecting head leading to a flow path when the pipe is deformed by the heading process. In the study, in order to prevent the folding in the inner wall surface of the pipe during the heading process, FE-analysis has been used in the die design.