• 한국산업융합학회 논문집
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• 제27권5호
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• pp.1175-1180
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• 2024

The fuel supply pipe connected to the hydrogen fueled vehicle hydrogen tank is very complicated. Therefore, the fixed portion of the pipe should be determined according to the external vibration. In particular, in order to avoid the resonance frequency range of the hydrogen fueled vehicle, it is necessary to examine the vibration characteristics of the fuel supply pipe and the stress concentration generation part for each frequency. Therefore, the purpose of this study is to understand the resonance potential for the natural frequency of the fuel supply pipe for hydrogen fueled vehicles and the excitation force(vibration of the motor etc.) applied to the external excitation frequency range(1-40Hz). Vibration characteristics were analyzed using the finite element method(FEM) to secure basic data for future seismic vibration tests of fuel supply pipes and to evaluate the safety of fuel supply pipe system.

• 한국연소학회:학술대회논문집
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• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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• pp.65-73
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• 2003

An experimental study on flame lift-off characteristics of propane jet flame highly diluted with nitrogen has been conducted introducing acoustic forcing with a tube resonant frequency. A flame stability curve is attained according to forcing strength and nozzle exit velocity for $N_2$ diluted flames. Flame lift-off behavior with forcing strength and nozzle exit velocity is globally categorized into three; a well premixed behavior caused by a collapsible mixing for large forcing strength, a coexistent behavior of well-premixed and edge flames interacting with well-organized inner fuel vortices for moderate forcing strengths, and edge flame behavior for small forcing strengths. Special focus is concentrated on the coexistent behavior of the flame base in lifted flame since this may give a hint to a possibility which the flame base behaves like a well-mixed premixed flame in highly turbulent lifted flames. It is also shown that the acoustic forcing to self-pulsating laminar lifted flame affects flame lift-off behavior considerably which is closely related to downstream flow velocity, mixture strength, effective fuel Lewis number, and flame stretch.

• 동력기계공학회지
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• 제19권3호
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• pp.22-28
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• 2015

A compression ignition type of diesel engine makes fuel efficiency better and $CO_2$ in the exhaust gas lower. Also it is suitable to apply alternative fuels(blended fuel) to the engine. The objective of this study is the emissions reduction of diesel engine with EF(Emulsified fuel). The emulsified fuel consists of diesel and peroxide($H_2O_2$) and Soot reduction without worsening of NOx emissions can be achieved by using thermal decomposition of the peroxide, i.e. the chemical effect of the OH radical in actual engine. For manufacturing emulsified fuel, a surfactant which is comprised of span 80 and tween 80 mixed as 9:1, was mixed with a fixed with 3% of the total volume in the emulsion fuel. In addition, considering the mixing ratio of the surfactant, the mixing ratio of $H_2O_2$ in the emulsified fuel was set as EF0, EF2, EF12, EF22, EF32, and EF42, respectively. Consequently, this study aims to obtain the optimization of fuel design(mixing) for the emulsified fuel applying to the diesel engine.

• International Journal of Automotive Technology
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• 제6권3호
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• pp.215-219
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• 2005

Liquefied petroleum gas (LPG) has been used as motor fuel due to its low emissions and low cost. A liquid direct injection system into a cylinder was suggested as a next generation system to maximize a fuel economy as well as a power. This study addresses the analysis of the LPG spray injecting from single hole injector. Two different test conditions are given, which are a fully developed spray case with various injection pressures and a developing spray case with ambient pressure variation. The LPG spray photographs are compared with the sprays of gasoline and diesel fuel at the same conditions, and the spray angles and penetration lengths are also compared, and then the spray behavior is analyzed. The LPG spray photos show that the dispersion characteristic depends very sensitively on the ambient pressure soon after injection. The spray angle is very wide in a low ambient pressure condition until the saturated pressure, but the angle is quickly reduced at the condition over the pressure. However, the down stream of the LPG spray shows much wider dispersion and less penetration than those of gasoline and diesel sprays regardless ambient pressure condition.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.23-26
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• 2007

Liquid water in flow channel is an important factor that limits the steady and transient performance of PEM fuel cells. A computational fluid dynamics study based on the volume-of-fluid (VOF) multi-phase model is conducted to understand the transport behavior of liquid water in flow channel. The liquid water transport in $180^{\circ}$ bends is investigated and the effect of chamfering is discussed. The effect of wall adhesion is also considered by varying the contact angle of channel surfaces. The result of this study is believed to provide a useful guideline for design optimization of flow patterns or channel configurations of PEM fuel cells.

• 동력기계공학회지
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• 제3권3호
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• pp.36-43
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• 1999

Many of thermodynamic-based diesel combustion simulations incorporated a model of fuel spray which attempts to describe how the spray develops according to time. Because the spray geometry is an essential aspect of the fuel-air mixing process, it is necessary to be calculated quantitatively for the purpose of heat release and emission analysis. In this paper, we proposed the calculating method of non-evaporation spray behaviors by injection rate shapes under actual operating conditions of diesel engine. We confirmed the utility of this calculating model as the calculated results were compared with the measured results. This calculating program can be applied usefully to study on the diesel spray behavior.

• 동력기계공학회지
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• 제18권3호
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• pp.5-13
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• 2014

In order to control emissions from engine, it is necessary to understand the mixture formation process of diesel spray. In this study, analysis of diesel fuel(n-Tridecane, $C_{13}H_{28}$) spray under a high temperature and pressure was performed by a general-purpose program, ANSYS CFX release 11.0, and the results of these are compared with experimental results of diesel fuel spray using the Exciplex Fluorescence Method. The simulation results of diesel spray is analyzed by using the combination of Large-Eddy Simulation(LES) and Lagrangian Particle Tracking(LPT), and then injection pressure was selected as an analysis parameter. Consequently, it was found that the experimental results and the numerical results are consistent with each other, and then in order to investigate the behavior characteristics of evaporative diesel spray, the effectiveness of the use of CFX of commercial code is definitely validated.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.59-62
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• 2008

The performance behavior of solid oxide fuel cell using reformate gas as fuels was investigated. When the pre-reformate gas was used without steam, the maximum power density was 50% lower than that using H2. This may be due to carbon deposition caused by the pyrolysis of remaining hydrocarbons. However, when the steam was added, the maximum power density showed a relatively small variation according to reformate gas. When pre-reformate gas with steam was fed into anode, the SOFC showed the stable performance without sharp voltage drop during 10h operation.

• 대한기계학회논문집B
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• 제29권4호
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• pp.477-484
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• 2005

Model fer the dynamic simulation of dynamic behaviors of a solid oxide fuel cell (SOFC) is provided. This model is based upon (1) coupled mass and heat transfer characteristics and (2) important chemical reactions such as electrochemical and reforming reactions in high temperature fuel cells such as SOFC. It is found that the thermal inertia of solid materials in SOFC plays an important role to the dynamic behavior of cell temperature. Dynamic characteristics of cell voltage, power, and chemical compositions with different levels of load change are investigated.

• Nuclear Engineering and Technology
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• 제30권2호
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• pp.173-179
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• 1998

The corrosion behavior of KOFA cladding which is a standard Zircaloy-4 manufactured by Westinghouse Specialty Metal Plant according to the Siemens/KWU's HCW (Highly Cold Worked) standard Zircaloy-4 specification was analyzed using the oxide measurement data of KOFA fuel irradiated in Kori-2 nuclear power plant. Analysis of the measured KOFA cladding oxidation showed that oxidation of KOFA cladding was lower than the design prediction based upon Siemens/KWU's HCW standard Zircaloy-4 cladding. Although the measured fuel rods have relatively low burnup and oxidation and the amount of the measured data are small, analysis of manufacturing and in-reactor operation conditions of KOFA cladding indicates that the differences in the manufacturing processes and chemical composition of the Siemens/KWU's HCW (Highly Cold Worked) standard Zircaloy-4 and KOFA cladding may have somewhat contributed to lower corrosion of KOFA cladding than the expected.