• Nuclear Engineering and Technology
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• v.49 no.8
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• pp.1629-1635
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• 2017

Reliable prediction of nuclear fuel rod behavior of nuclear power reactors constitutes a basic demand for steady-state calculations, design purposes, and fuel performance assessment. Perfect design of fuel rods as the first barrier against fission product release is very important. Simulation of fuel rod performance with a code or software is one of the fuel rod design steps. In this study, a software program called MARCODE is developed in MATLAB environment that can analyze the temperature distribution, gap conductance value, and fuel and clad displacement in both solid and annular fuel rods. With a comparison of the maximum fuel temperature, fuel average temperature, fuel surface temperature, and gap conductance in solid and annular fuel, the effects of a central hole on the fuel temperature distribution are investigated.

• Journal of Power System Engineering
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• v.12 no.6
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• pp.64-69
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• 2008

The spatial fuel distribution of the stratified charge of a high pressure 6-hole injector was examined in a single cylinder optical direct injection spark ignition(DISI) engine. The effects of in-cylinder charge motion, and fuel injection pressure, and coolant temperature were investigated using a planar LIF(Laser Induced Fluorescence) technique. It was confirmed that the in-cylinder tumble flow played more effective role in the spatial fuel distribution of the stratified charge than the swirl flow during the compression stroke and the fuel distribution area increased due to the activation of the fuel vaporization by the increase of the coolant temperature. But, the increase of the fuel supplying pressure could not change the pattern of the fuel vapor distribution against the expectation.

• Journal of the Korean Society of Combustion
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• v.19 no.4
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• pp.8-13
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• 2014

Flow distribution of fuel nozzles for a combustor in a micro gas turbine is numerically investigated. The fuel supply system for the present study has 12 single nozzles with a diameter of several hundred micrometers. A uniform temperature distribution of a combustor outlet should be achieved for maximizing the lives of the turbine blades and nozzle guide vanes. For this, it is very important to uniformly supply fuel to a combustor. In order to investigate flow distributions of fuel nozzles, numerical models for fuel nozzles are made and solved by a commercial code, ANSYS FLUENT. An effect of a fuel nozzle diameter and fuel flow rates on flow distribution of fuel nozzles is numerically investigated. As a result, non-uniformity is increasing as a diameter of a single fuel nozzle increases. Finally, an appropriate diameter of a single fuel nozzle is suggested.

• Tribology and Lubricants
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• v.30 no.1
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• pp.52-58
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• 2014

Because food crops serve as the raw materials for biodiesel, the increasing use of biodiesel as an alternative fuel can lead to adverse effects such as food price inflation and may contribute to global starvation. To solve these problems, efforts are being made to explore various nonedible raw materials for producing biodiesel. Different raw materials impart different fuel characteristics to biodiesel. In this study, we synthesized pure fatty acid methyl ester (FAME), which is a biodiesel component, and then analyzed its fuel properties. The fuel properties of pure FAME would be useful in producing biodiesel from various new raw materials.

• Journal of ILASS-Korea
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• v.2 no.4
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• pp.36-46
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• 1997

The present study investigated the effects of MTV(Manifold Throttle Valve) on the fuel distribution and the flame stability in a SI engine at cold, idling condition. For the quantitative measurement of fuel distribution with PLIF method, compensating techniques of various factors such as laser beam nonuniformity, background image and local OTF nonuniformity were developed. As a result, it was found that MTV had a positive effect on the air-fuel mixing and flame stability.

• Journal of Hydrogen and New Energy
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• v.34 no.4
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• pp.358-368
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• 2023

The fuel cell market is expected to grow rapidly. Therefore, it is necessary to scale up fuel cells for buildings, power generation, and ships. A multi-stack system can be an effective way to expand the capacity of a fuel cell. Multi-stack fuel cell systems are better than single-stack systems in terms of efficiency, reliability, durability and maintenance. In this research, we developed a residential fuel cell stack and system model that generates electricity using the fuel cell-photovoltaic hybrid system. The efficiency and hydrogen consumption of the fuel cell system were calculated according to the three proposed power distribution methods (equivalent, Daisy-chain, and optimal method). As a result, the optimal power distribution method increases the efficiency of the fuel cell system and reduces hydrogen consumption. The more frequently the multi-stack fuel cell system is exposed to lower power levels, the greater the effectiveness of the optimal power distribution method.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.974-985
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• 2017

Although the number of registered cars in South Korea is about 22million but, there is no national standard for automobile reference fuel in South Korea. Reference fuel is the fuel used for certificating vehicle performance, emissions and fuel economy. Now, domestic market fuels are used as reference fuel. However, the quality of domestic market fuel is constantly changing by seasonal and fuel manufacturers. It may effect vehicle performance, emissions and fuel efficiency test result. On this study, market diesel fuel quality was monitored and reference fuel standard(draft) was set by reflecting market fuel monitoring result. Reference fuel standard(draft) was applied to CRDI engine.

• Journal of Power System Engineering
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• v.20 no.4
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• pp.52-62
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• 2016

Nowadays, emissions of a vehicle are been getting by testing on a chassis dynamometer and a test modes. Also, fuel efficiency is calculated by carbon-balance method that is applying the emissions(CO, THC and $CO_2$) to the fuel calculation formular. In Korea, before 2014, the formular did not include the fuel factors (density, net heat value and carbon weight fraction), but the constants were based on the fuel properties of 2000s. So, this formular did not consider a characteristic of test fuel property that was changed when progressing fuel efficiency test. The characteristics of test fuel property which was distributed in domestic have a difference of quality depending on production regions and oil-refining facilities. Because the fuel properties are variable value during refineries, crude oils and blending contents of a bio-fuel, vehicle fuel is changed for each test. Therefore, the fuel qualities need to apply for a fuel economy test. In this paper, changing patterns of a fuel properties were reviewed during history of fuel standards. Also, the appropriateness of the methods was discussed by calculating and comparing fuel economies with the fuel factors and the constants.

• Journal of Power System Engineering
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• v.21 no.6
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• pp.46-55
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• 2017

Due to the arise of natural disasters caused by global warming, consumers have more interest in the fuel efficiency of their vehicles, and fuel efficiency became an important factor in comparing vehicles. In this market situation, methods to measure fuel efficiency has become one of the main interests of vehicle related organizations and laboratories, and the current method to measure fuel efficiency is to follow the notification established by the ministry of trade, industry and energy, ministry of environment, and the ministry of land, infrastructure and transport. In this study, we analyze the influence of vehicle fuel efficiency according to test temperature and cooling fan condition which have the possibility to cause difference in fuel efficiency. The analysis results of the influence of the fuel efficiency according to the test temperature, the difference of the fuel efficiency of the test temperature ($21{\sim}29^{\circ}C$) within the allowable range of the notification showed a maximum difference of 2.9%. Therefore, it is necessary to consider the introduction of a test method that permits only the temperature change based on the reference point as the allowable range even in the test within the allowable range. The analysis of the influence of the fuel efficiency according to the cooling method showed no significant effect, and it seems reasonable to maintain the test method of the current notification.

• Tribology and Lubricants
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• v.36 no.6
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• pp.385-390
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• 2020

It rains heavily, such as long rain and typhoons, during a typical rainy season in Korea. In this season, several fuel contamination accidents by water and vehicular problems caused by water contaminated fuel occur. Many research groups have studied the effects of water contaminated fuel on vehicles and environment. However the characteristics of water contaminated fuel have not been studied. In this study, we prepared diesel samples with a constant ratio of water (0~30 volume %) using an emulsifier. Then, we analyzed these diesel samples for their representative fuel properties. In the analytical results, diesel with 30% water showed an increase in fuel properties such as density (823→883 kg/㎥), kinematic viscosity (2.601→6.345 ㎟/s), flash point (47→56℃), pour point (-22→2℃), CFPP (cold filter plugging point) (-17→20℃) and copper corrosion number (1a→2a). The low temperature characteristics, such as low pour point and CFPP, blocks the fuel filter in the cold season. In addition, water contaminated diesel decreases lubricity (190→410 ㎛) under high frequency reciprocating rig (HFRR) and derived cetane number (54.81→34.25). The low lubricity of fuel causes vehicle problem such as pump and injector damage owing to severe friction. In addition, the low cetane diesel fuel increases exhaust gases such as NOx and particulate matters (PM) owing to incomplete combustion. This study can be used to identify the problems caused by water contamination to vehicle and fuel facilities.