• 한국분무공학회지
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• 제17권3호
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• pp.152-157
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• 2012

This investigation decribes the effect of the combustion and emission characteristics of HCNG engine according to the high purity hydrogen contents. The HCNG fuel was made by the mixture with a high purity hydrogen ($H_2$) and a natural gas. The test vehicle was applied to the bi-fuel (Gasoline and CNG) system and this system was modified from the fuel supply and fuel tank. In addition, the three premixed HCNG fuels with mixed rate of 10, 20 and 30% of hydrogen were used to maintain the safety. In order to analyze the combustion characteristics of HCNG and CNG, the fuel was injected in the combustor with constant volume. The exhaust emission from light duty vehicle with bi-fuel system was analyzed by a chassis dynamometer and emission analyzer. From these results, the reduction rate of NOx emission increased in the HCNG fuel and emission amount of THC and CO shows a similar level with CNG fuel. This study can be utilized the basic data for the development of a new business plans related with HCNG engines.

• 한국자동차공학회논문집
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• 제2권6호
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• pp.102-109
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• 1994

As a fundamental study to apply high pressure injection system to direct injection diesel engine, fuel injection system and constant volume combustion chamber were made and the behaviors of evaporating spray with the variation of injection pressure and the ambient gas temperature were observed by using high speed camera, and the combusion characteristics with the variation of injection pressure and A/F ratio were analyzed. As injection pressure increases, spray tip penetration and spray angle increase and, as a results spray volume increases. This helps an uniform mixing of fuel and air. Spray liquid core length decreases as ambient gas temperature increases, while it decreases as injection pressure increases but the effect of ambient gas temperature is dorminant. As injection pressure increases, ignition delay is shortened and combustion rate being raised, maximum heat release rate increases. It become clear that High injection pressure has high level of potential to improve the performance of DI-diesel engine.

• 한국노년학
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• 제38권2호
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• pp.329-349
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• 2018

본 연구의 목적은 노년기 연령집단별로 사회활동 참여유형이 다른지와 연령집단별로 행복감에 미치는 사회활동 유형은 무엇인지를 조사하는 것이다. 한국고령화패널연구(KLoSA), 5차(2014) 자료를 활용하였으며 5차 시점에서 65세 이상이면서 자녀와 동거하지 않는 노인 3,273명을 대상으로 교차분석, 일원변량분석, 위계적 다중회귀분석(hierarchical multiple regression analysis)을 실시하였다. 연구결과, 경제활동 참여 비율은 연령대가 높아질수록 낮아졌으며, 여가활동은 연소노인이 중고령노인이나 초고령노인집단에 비해 참여수준이 높았다. 가족활동은 연소노인에 비해 중고령노인이나 초고령노인 집단에서 참여수준이 높았고, 그 외의 친목활동과 종교활동은 연령 집단 간 참여수준의 차이를 보이지 않았다. 연령집단별 행복감에 유의미한 영향을 주는 사회활동 유형을 회귀분석 한 결과, 연소노인 집단에서는 경제활동을 제외한 여가활동, 친목활동, 종교활동, 가족활동이 노인의 행복감에 정적으로 유의미한 영향을 미쳤으나, 중고령노인 집단에서는 친목활동과 가족활동이, 초고령집단에서는 가족활동만이 노인의 행복감에 정적으로 유의미한 영향을 미쳤다. 본 연구결과는 연령집단에 따라서 참여하는 사회활동 유형과 그 영향력이 달라질 수 있음을 입증하였다. 본 연구는 다양화되어가는 노인인구의 욕구를 경험적으로 검증하였다는데 그 의의가 있다.

• 항공우주기술
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• 제6권1호
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• pp.146-156
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• 2007

본 논문에서는 KSLV-I 상단부 시험을 목적으로 실물형으로 제작된 킥모터 조합체에 대한 TVC 구동특성시험과 분석 결과에 대해 정리하고자 한다. 실물형 킥모터 조합체는 추진제 대신 물을 채울 수 있는 구조로 되어서 수압으로 연소압 상황을 모사하면서 챔버압에 따른 플렉스씰 TVC 노즐의 특성을 파악할 수가 있으며, 챔버압에 따른 TVC 정적 및 동적특성 변화 또한 분석할 수가 있다. 실물형 킥모터 조합체에 대한 TVC 구동 시험을 수행하는 데 필요한 설비 구축 과정에 대해서 개략적으로 설명하고, TVC 정적 시험을 통한 제어 특성 분석 결과 및 TVC 동적 시험을 통한 동특성 분석 결과를 정리한다. 이러한 결과들은 KSLV-I 의 TVC 자세제어 정밀도를 높이는 데 있어서 중요한 역할을 담당하고 있다.

• 한국분무공학회지
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• 제19권3호
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• pp.115-122
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• 2014

As a demand for an automobile increases, air pollution and a problem of the energy resources come to the fore in the world. Consequently, governments of every country established ordinances for green-house gas reduction and improvement of air pollution problem. Especially, as international oil price increases, engine using clean energy are being developed competitively with alternative transportation energy sources development policy as the center. Bio ethanol, one of the renewable energy produced from biomass, gained spotlight for transportation energy sources. Studies are in progress to improve fuel supply methods and combustion methods which are key features, one of the engine technologies. DI(Direct Injection), which can reduce fuel consumption rate by injecting fuel directly into the cylinder, is being studied for Green-house gas reduction and fuel economy enhancement at SI(Spark Ignition). GDI(Galoine Direct Injection) has an advantage to meet the regulations for fuel efficiency and $CO_2$ emissions. However it produces increased number of ultrafine particles, that yet received attention in the existing port-injection system, and NOX. As fuel is injected into the cylinder with high-pressure, a proper injection strategy is required by characteristics of a fuel. Especially, when alcohol type fuel is considered. In this study, we tried to get a base data bio-ethanol mixture in GDI, and combustion for optimization. We set fuel mixture rate and fuel injection pressure as parameters and took a picture with a high speed camera after gasoline-ethanol mixture fuel was injected into a constant volume combustion chamber. We figured out spraying characteristic according to parameters. Also, we determine combustion characteristics by measuring emissions and analyzing combustion.

• 한국분무공학회지
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• 제17권4호
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• pp.178-184
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• 2012

The aim of this study was to compare the spray characteristics of a typical fuel (100% diesel, DME) and diesel-DME blended fuel in a constant volume combustion chamber (CVCC). The typical fuel (100% diesel, DME) and diesel-DME blended fuel spray characteristics were investigated at various ambient pressures (pressurized nitrogen) and fuel injection pressures using a common rail fuel injection system when the fuel mixture ratio was varied. The fuel injection quantity and spray characteristics were measured including spray shape, penetration length, and spray angle. Common types of injectors were used.

• 한국환경과학회지
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• 제15권6호
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• pp.601-606
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• 2006

The coal gasification fuel is important to replace petroleum fuel. Also they have many benefits for reducing the air pollution. Measurements on the combustion characteristics of synthetic gas from coal gasification have been conducted as compared with LPG in constant volume combustion chamber. The fuel is low caloric synthetic gas containing carbon monoxide 30%, hydrogen 20%, carbon dioxide 5%, and nitrogen 45%. To elucidate the combustion characteristics of the coal gasification fuel, the combustion pressures, combustion durations, and pollutants(NOx, $CO_2$, CO) are measured with equivalence ratios($\phi$), and initial pressures of fuel-air mixture in constant volume chamber. In the case of the coal gasification fuel, maximum combustion pressure and NOx concentration are lower rather than LPG fuel. However CO and $CO_2$ emission concentration are similar to that of LPG fuel.

• Journal of Advanced Marine Engineering and Technology
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• 제25권2호
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• pp.395-402
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• 2001

The gasoline engine tends to high performance, fuel economy, small-sized. Therefore, it is necessary to solve the problems on thermal load, abnormal combustion, etc, in the engine, Thine film instantaneous temperature measurement probe was made. And the manufactural method of probe was established. The instantaneous surface temperatures in the constant volume combustion chamber were measured by this probe and the heat flux was obtained by Fourier analysis. The authors measured the wall temperature of combustion chamber and computed the heat flux through the cylinder wall in order to understand the combustion characteristics depending on height of probe. For achieving this goal, the thin film instantaneous temperature probe was developed for analyzing the instantaneous surface wall temperature and unsteady heat flux on the constant volume combustion chamber.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1998년도 춘계 학술발표회 논문집
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• pp.9-14
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• 1998

석탄가스화 복합발전시스템(Integrated Gasification Combined Cycle, IGCC)은 기존의 미분탄 연소 발전 방식에 비해 발전효율이 5-10%이상 높고, 공해물질 배출 특성에 있어서도 SOx와 NOx를 각각 95% 및 75% 이상 감소시키고 재는 용응 슬러 형태로 처리하는 발전시스템이다. 이와 같은 고효율 및 환경 친화적인 특성으로 인하여 IGCC 시스템은 차세대 석탄화력 발전 방식으로서 각광받고 있으며, 이미 선진 공업국들은 70년대 석유파동 이후 IGCC 기술의 개발을 활발히 진행하여, 최근에는 250MW 이상 출력의 상용화급 플랜트를 가동 또는 건설 중에 있으며, 머지않아 상업화에 도달할 전망이다. 또한 국내에서도 최근 전력 수요의 급증과 전 세계적으로 확산되고 있는 환경 규제의 강화 등으로 우리의 실정에 맞는 IGCC 공정의 개발이 활발히 진행되고 있다. (중략)

• 한국자동차공학회논문집
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• 제16권1호
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• pp.152-157
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• 2008

The biodiesel becomes one of the favorite alternative fuel applied to diesel engines. This research aims to understand the physics of spray and combustion characteristics of a biodiesel fuel in a constant volume chamber. For spray visualization, biodiesel was injected into a combustion chamber and a high speed camera was applied at various combustion conditions. To investigate heat-release rates and flame propagations, spark was ignited on a hydrogen fuel for the premixed combustion and then biodiesel was injected directly. In addition, parametric study was made by various geometries of combustion chambers and temperatures of fuels and injection pressures. This technology may contribute to improve the performance of bio-diesel engine and reduce emissions in future.