• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.371-373
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• 2014

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.1
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• pp.61-67
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• 2015

The cooling of hot exhaust gas is an important issue for the construction of combustor test facility. Water spray is an effective method for exhaust gas cooling due to its large latent heat in process of evaporation. In this study, 1-D analysis has been performed based on continuity, energy conservation, and saturated vapor property to understand water spray cooling of combustion gas. In the exhaust duct of combustor test facility, the injected water decreases combustion gas temperature, and evaporates in the combustion gas. However, some of the injected water is collected in the sump due to condensation. The evaporation of water helps combustion gas cooling, but causes pressure increase inside the exhaust duct due to increase of vapor pressure. These phenomena has been analyzed by 1-D modeling in this study. From 1-D analysis, the adequate mass flow rate of water spray to cool combustion gas and to avoid excessive pressure rise inside the exhaust duct has been decided.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.180-188
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• 1992

By means of the compatibility according to solving environmental pollution and energy problem due to the emissions of NOx and smoke from diesel engine this paper experimentally inspected the effect of using emulsified fuel, gas oil-water, for combustion characteristic, that is combustion pressure, pressure rise rate, heat generating rate, the period of ignition delay and specific fuel consumption, and CO, HC, NOx concentration and smoke density. When using emulsified fuel, as a water addition rate was increased, combustion pressure, pressure rise rate and heat generating rate was increased, the period of ignition delay was lengthening, the specific fuel consumption was some what increased in contrast to diesel fuel in low load, but deceased in high load region. And NOx concentration was decreased, CO concentration was increased in low load, but decreased in high load region, HC concentration was increased in contrast to diesel fuel in all region.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.1
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• pp.240-249
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• 1994

The basic experiments for designing the effective gas turbine combustor were performed. There are several factors that define the characteristics of gas turbine combustor. Among them, experiment was focused on swirl effects by three types of swirler with different swirl numbers(0.0, 0.38, and 0.62). Particularly, an interest was concentrated on primary zone where the flame characteristics of total combustor was dominated strongly and secondary zone where the remaining unburned gas was reacted again or cooling effect was done according to degree of swirl intensity. For this study, following measurements have been carried out, that is, time mean and fluctuating temperature, exhaust gas composition including NO concentration, and ion current. From this study, it was found that swirl intensity affects largely not only flame style but also emission formation, furthermore that it is important to select proper swirl intensity.

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.456-461
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• 2012

To verify the utilization of biomass as energy, the combustion characteristic has been studied by an experimental combustion furnace under an isothermal and non-isothermal combustion. The wood pellet, rice straw and rice husk were used as biomass samples in this work. The characteristics of emission gases, dusts and residues from biomass combustion have been analyzed and compared with those of reuse derived fuel (RDF). From isothermal combustion experiments, it was found that the incomplete combustion of rice straw was greater that that of rice husk, wood pellet and RDF. This is due to the fact that the combustion reaction rate of the rice straw was faster than that of other samples, and the oxygen concentration in rice straw combustion was rapidly decreasing. It was also found that $NO_{X}$ concentration of emission gas from wood pellet combustion was the lowest. From non-isothermal combustion experiments, it was found that all samples were burned before $900^{\circ}C$. Also, the temperature range of $NO_{X}$ emission was similar to that of CO emission, on the other hand, $SO_{2}$ was emitted at a higher temperature than that of CO emission.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1064-1069
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• 2014

The use of emulsified fuel and EGR (Exhaust gas recirculation) system are effective methods to reduce NOx emission from diesel engines. In general, it is considered that EGR method influences diesel engine combustion in three different ways: thermal, chemical and dilution effect. Among others, the thermal effect is related to the increase of specific heat capacity due to the presence of $CO_2$ and $H_2O$ in inlet air. Meanwhile, emulsified fuel method of utilizing latent heat of vaporization and miro-explosion has been recognized as an effective technique for reducing diesel engine emissions. In this paper, an author studied on combustion and emission characteristics by using emulsified fuel (EF, Light oil : 80% + Water : 20%) and EGR (30% EGR ratio) system. And the effect of fuel injection pattern control was investigated.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.10
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• pp.637-644
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• 2016

The purpose of this study is to understand the characteristics of unburned carbon (UBC) and NOx emissions for pulverized coal when air staging combustion is applied. A two-staged drop tube furnace capable of applying air staging combustion was designed and installed. The combustion of sub-bituminous (Tanito) has been investigated. UBC and the NOx concentration were measured under various temperatures and stoichiometric ratios in unstaged and staged combustion. As a result, UBC decreased and the NOx concentration increased with an increase in stoichiometric ratio and temperature. In particular, the NOx reduction mechanism was activated when the temperature in the fuel rich zone increased. Both UBC and the NOx concentration decreased as the temperature increased in the fuel rich zone. A high NOx reduction effect was obtained, compared to the UBC increase, when the air staging technique was applied.

• Journal of the KSME
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• v.34 no.12
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• pp.929-939
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• 1994

최근 환경문제와 관련하여 정제된 석유 연료가 아닌 천연가스와 같은 연료의 사용이 증가하면서 산업용 가스터빈의 연소기술에 대한 관심이 집중되고 있다. 가스터빈 연소로 생성되는, 환경을 위협하는 오염물은 연기, 수증기, 일산화탄소(CO), 미연 탄화수소, $NO_{x}$, $SO_{x}$ 등이 있다. 수증기 및 일산화탄소는 지구 온실화에 영향을 미치고 있으나 그다지 심각한 정도는 아 니며, $SO_{x}$는 독성이 있으나 연료 정제시 제거되어질 수 있다. $NO_{x}$는 지구의 오 존층을 파괴하여 생태계를 위협하기 때문에 오염 배출물중 가장 심각하게 고려되어지고 있다. 미국에서는 법으로 산업용 가스터빈의 $NO_{x}$의 양을 규제하고 있는데 15% 산소배출농도에 대하여 1984년에 75ppm에서 1993년에 30ppm으로 낮추어 규제하고 있다. 일본도 미국과 비슷한 수준으로 규제하고 있으며, 따라서 최근의 가스터빈 연소기술은 저 $NO_{x}$연소기에 대한 것으로 저$NO_{x}$연소에 관한 개론 및 가스터빈 연소기의 저$NO_{x}$화 방법, 그리고 미 국과 일본의 최근의 저$NO_{x}$연소기 개발동향에 대하여 다루고자 한다.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.21-22
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• 2006

디젤엔진에서 배출되는 배기가스 중의 주요 오염물질 중의 하나인 NOx(질소산화물)는 대부분 고온의 연소 과정에서 발생하고, 발생량은 연소온도에 따라 결정되는 것으로 알려져 있다. 또한 연료의 연소 중에 물이 첨가되면 연소공기의 비열 증가에 의하여 연소온도가 감소하여 NOx 발생량이 급격하게 감소하게 되는데, 연소실에 물을 첨가하는 방법으로는 유화연료, 직접물분사, 흡기가습 등이 있다. 이중 흡기가습은 구조가 간단하면서 NOx 저감효율이 가장 높은 것으로 알려져 있다. 본 연구는 당사 고유모델 중형엔진인 힘센엔진에 흡기가습 기술을 적용하여 연소성능 및 NOx 저감효과 등을 시험하고, 흡기가습 시스템의 상용화 모델 개발을 위한 기초 데이터를 확보하기 위해 수행되었다.

• Analytical Science and Technology
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• v.28 no.3
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• pp.236-245
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• 2015

Recently, candles have been widely used to create a romantic atmosphere and to heat tea. In this study, a small combustion chamber for candle was designed using an 0.008 m³ bell jar. The emission factors of combustion products were then measured. The combustion chamber includes a glass dish, which prevents candle flame from affecting the composition of the gas emitted through the exhaust outlet. The outlet in the combustion chamber was designed as a cone shape, and it was lengthened to prevent flow from the outside, which could affect the homogeneous composition of the exhaust gas. The temperature at the outlet of the chamber was 34 ℃~41℃. The major combustion products of the candle, such as such aldehydes and acids, contained oxygen. The mass specific emission rates of benzene, toluene, ethylbenzene, and TVOC were 0.04 μg/g, 0.01 μg/g, 0.02 μg/g, and 3.81, respectively. The mass specific emission rates of formaldehyde, acetaldehyde and benzaldehyde were 4.48 μg/g, 1.09 μg/g, and 0.67 μg/g, respectively. Considering the different compositions of the candle samples, their mass specific emission rates were similar to those obtained by using a large chamber 0.17 m³~50 m³ in size.