• Fire Science and Engineering
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• v.27 no.6
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• pp.89-96
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• 2013

The purpose of this study is to check the fire origin and cause of the fire by observing the shape of the flame propagation in air-conditioner indoor unit through the fire tests. We supposed that the flame is spread from the surroundings to the top of the air-conditioner and ignited on top of the air-conditioner with n-heptane. And then repeated this experiment twice under the same conditions. After the ignition, refrigerant filled in air-conditioner and lubricating oil exploded with large explosion and flame having high temperature and pressure belched out rapidly due to bursting refrigerant pipe linked air-conditioner between 734 seconds and 559 seconds. After result of checking the combustion residue we found that almost all of that was lost except a part of the evaporator, motor and metal. The position of short-circuit traces of wiring for the air-conditioner ignited itself is similar to that of fire damage by external flame. Therefore, we verified that it is not certain to determine the ignition cause and point by only the shape of the combustion residues.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.303-307
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• 2008

In this study, we have carried out the cone calorimeter test to examine the thermal characteristics, such as total smoke production(TSP), smoke temperature and oxygen consumption, of significant parts of above trees which are representative species of Young Dong Province of Korea. The smoke production of dead leaves and living leaves of pinus densiflora was increased rapidly at the early period of combustion. So the total smoke production of this parts was 8.3 times higher than other parts. The TSP of branches and barks of quercus dentata was 14.4 and 7.2 times higher than of pinus densiflora respectively. And also the maximum smoke temperature was about $338.35{\sim}353.25\;K$. The significant difference of oxygen consumption was not detected for dead leaves, branches and barks. However, the oxygen consumption of living leaves which have high percentage of moisture content is the lowest.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.1
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• pp.7-15
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• 2018

In this study, AOT that is used as a surfactant in various industries was applied to an HTPB/AP solid propellant. AOT is one of the anionic surfactants, and there have been cases where AOT was reported to induce self-extinguishable properties in propellants overseas. In this study, solid propellants using AOT were prepared, and their properties and combustion characteristics were investigated. The combustion rate of the AOT-applied propellant drops sharply when the pressure reaches a certain value during combustion. Further, the density and hardness of the propellant are lower than those of conventional HTPB/AP propellants.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.734-739
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• 2009

Characteristics of pyrolysis, partial oxidation, combustion of chlorella, which is one species of micro-algae, were determined by using thermobalance reactor(I.D. 5.5 cm, Height 1 m). Effect of reaction temperature($500{\sim}800^{\circ}C$), water content in chlorella(0~60%), and oxygen content(0~21vol%) on thermal decomposition of chlorella were also determined and analyzed to investigate the kinetic characteristics of pyrolysis, partial oxidation and combustion. As the temperature and partial pressure increases, the carbon conversion increases. In case of pyrolysis, carbon conversion and reactivity sharply decreased with increasing moisture content. However, carbon conversion and reactivity decreased at 60% water content in case of partial oxidation and combustion. As reaction temperature and oxygen content increased, carbon conversion increased and the combustion reaction rate equation for chlorella has been presented. $\frac{dX}{dt}=(7.41{\times}10^{-1})$exp$\left(-\frac{19600}{RT}\right)(P_{O_{2}})^{0.209}(1-X)^{2/3}$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.1
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• pp.103-110
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• 2012

The flow field, fuel-air mixing, and behaviors of turbulent flames have been investigated using the large eddy simulation (LES) numerical technique in a premixed swirl combustor equipped with EV double cone burners. Recirculation zones are generated by the swirl burner, and lean premixed flames are formed within a distance of 0.2 m from the tip of the burner. NOx emission of 0.46 ppm is predicted at 1 atm and an air/fuel ratio of 38.7. However, most of the CO generated in a flame front continues to be oxidized as it moves toward the exit, and CO emission of 5.45 ppm is predicted at the exit. The NOx emission can be reduced by decreasing the pressure and air/fuel ratio. The characteristics of NOx emission have been investigated through RANS simulations for various fuel injection types, and it is found thereby that five-lance-hole injection produces the lowest NOx emission rate.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.2
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• pp.97-107
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• 2017

This study is the second investigation on the steady flow characteristics of an SI engine with a semi-edge combustion chamber as a function of the port shape with varying evaluation positions. For this purpose, the planar velocity profiles were measured from 1.75B, 1.75 times of bore position apart from the bottom of head, to 6.00B positions using particle - image velocimetry. The flow patterns were examined with both a straight and a helical port. The velocity profiles, streamlines, and centers of swirl were almost the same at the same valve lift regardless of the measuring position, which is quite different from the case of the pent-roof combustion chamber. All the eccentricity values of the straight port were out of distortion criterion 0.15 through the lifts and the position. However, the values of the helical port exceeded the distortion criterion by up to 4 mm lift, but decreased rapidly above the 3.00B position and the 5 mm lift. There always existed a relative offset effect in the evaluation of the swirl coefficient using the PIV method due to the difference of the ideal impulse swirl meter velocity profile assumption, except for the cylinder-center-base estimation that was below 4 mm of the straight port. Finally, it was concluded that taking the center as an evaluation basis and the assumption about the axial velocity profile did not have any qualitative effect on swirl evaluation, but affected the value owing to the detailed profile.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.1-10
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• 2023

Due to the development of the industrial revolution, regulations on exhaust emissions have been continuously strengthened to reduce the rapidly increasing greenhouse gas emissions. The use of environmentally friendly fuels is essential to meet these regulations. Hydrogen has been attracting attention as a future environmentally friendly fuel, but due to its material properties, it faces significant challenges in handling and storage. As an alternative, ammonia has been proposed. Ammonia can be easily liquefied at room temperature compared to hydrogen and has a high energy density. In order to examine the applicability of ammonia as an engine fuel, experiments were conducted to investigate the effects of changes in combustion control parameters in a direct injection ammonia combustion engine. The experiments were conducted by varying two variables: spark timing and excessive air ratio. Observations were made on combustion stability and the trends of exhaust emissions such as nitrogen oxides and unburned ammonia under the conditions of an engine speed of 1,500 rpm and medium to high loads (brake torque of 200 Nm). By optimizing the combustion control parameters, conditions for stable combustion even when using ammonia as the sole fuel were identified, and plans are underway to apply strategies for future expansion of the operating range.

• Journal of the korean Society of Automotive Engineers
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• v.7 no.1
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• pp.12-17
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• 1985

주위기체와 다른 기체를 간헐적으로 또는 단발로 분사한 경우, 분류내의 분사체의 농도는 시간에 따라 급격히 변화한다. 수ms인 전자식기체 채취밸브를 이용해서 기체를 채취하고, 가스마토그 라프 등에 의해 가스분석을 행하는 방법이 있고 주로 피스톤식 내연기관의 연소실내 농도의 측 정에 이용되고 있다. 이 방법은 밸브 열립시간을 단축시켜도 약 1ms가 한도이고 시간분해능력도 1ms정도가 최단시간이다. 또 동일한 장소에서 농도의 시간경과를 얻는 데에는 각각의 시간에 대해서 기체의 채취와 분석을 행하지 않으면 안되어 실제시간의 농도측정이 불가능하다는 결점이 있다. 최근 레이저 응용기술의 진보에 의해 라만산란, 레리산란, CARS법 등의 농도순간측정이 가능해지고 있고, 점차 현실화되어가고 있다. 이들의 방법은 국소의 순간농도뿐만 아니라 온도의 동시측정도 가능하게 하는 특징을 갖고있다. 그러나 레이저에 의한 측정장치는 현시정에서는 아직 가격이 고가이고 광학계의 설치 등, 실험상의 조작이 복잡한 것 등의 결점을 갖고 있다. 본 고에서는 최근 진전이 현저하고 실용화에 대한 확신을 갖고 있는 열선농도Probe에 의한 순간농 도의 측정방법을 소개하고자 한다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1998.05a
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• pp.73-78
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• 1998

상용 IGCC발전소의 특징적 공정흐름에 대한 분석기술의 확보를 위해 PDU급 IGCC발전계통에 대한 성능평가와 NOx 배출에 대한 모델링을 수행하였다. 향후 IGCC발전소 건설시 선정가능성이 있는 4가지 가스화 공정에서 생산되는 석탄가스를 연료로 하고, 그 발전계통의 대상 가스터빈은 산업현장에서 사용되고 있는 GE사의 LM1600PA를 선정하였다. 석탄가스는 천연가스에 비해 가스터빈의 효율과 출력 상승을 가져오나, 이와 동시에 압축기 탈설계점 작동문제를 야기 시킬 수 있다. 또한 NOx 발생량은 석탄가스 연소시 급격히 증가하며, NOx 제어를 위해 질소분사가 이루어져야 함을 알 수 있었다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.143-146
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• 2011

2009년 11월 14일 발생한 부산 실내사격장 화재와 관련하여 조사내용을 토대로 화재 시뮬레이션용 전선유체역학 모델인 FDS를 이용하여 재현하였으며, 시뮬레이션 결과와 화재당시 녹화된 CCTV 영상을 비교하였다. 2층 발사실에서 시작된 화재는 급격히 연소가 진행되어 약 3초 후에 휴게실로 확산되며, 약 7초 후에는 계단 및 1층 홀을 지나 사람들이 통행하는 인도에까지 연기가 분출되는 것으로 나타났다. 시뮬레이션 결과는 2층 발사실과 휴게실에 녹화된 CCTV 영상 및 1층 홀 옆의 귀금속가게에 녹화된 CCTV 영상과 거의 일치하였다.