• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.375-378
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• 2011

The combustion characteristics of fuel-rich gas generator which could be adopted to Ducted Rocket propulsion system is investigated. The gas generator is designed considering the design requirements of propulsion system then solid fuel, which is developed by reducing the contents of oxidizer and increasing the contents of metallic solid particle, is loaded in the manufactured gas generator. The results of combustion test shows the necessity of the special analysis tool for estimating the gas generator performance where multi-phase flow of fuel-rich gas exists.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.293-298
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• 2011

The combustion and flow-rate control characteristics of fuel-rich gas generator which could be adopted to Ducted Rocket propulsion system are investigated. The gas generator is designed considering the design requirements of propulsion system and solid fuel for fuel-rich combustion is developed then adopted to ground test. The results of combustion test show the necessity of the special analysis tool for estimating the gas generator performance where multi-phase flow of fuel-rich gas exists. During the flow-rate control test, characteristics of gas generator pressure with the angle of valve are analyzed and, method to estimate the pressure of gas generator is suggested using the relation between the valve exit area and discharge coefficient.

• Fire Science and Engineering
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• v.28 no.1
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• pp.44-51
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• 2014

Smoke from fire is a mixture of combustion gases and particles which include micro-droplets formed from condensed organic vapors and carbonaceous agglomerates. The inhalation of smoke particles causes adverse health effects, and it is prerequisite for the hazard and risk analysis of the smoke particles to know how they behaviour in the respiratory tract. The characteristics of the absorption and adsorption of toxic gases and the amount and location of the particle deposition within the respiratory tract that determine the adverse health effects are related to the morphology and the size distribution of smoke particles. In the present work, as a preliminary study for the adverse health effects of smoke particles, the morphologies of the smoke particles from combustible materials were investigated for each fire stage: smouldering, well-ventilated flaming, small under-ventilated flaming, fully-developed under-ventilated fire. The steady-state tube furnace method given in ISO/TS 19700 was used for the generation of smoke particles. The fire stages were controlled by changing furnace temperature and equivalent ratio. The morphologies were analyzed by using Transmission Electron Microscope (Bio-TEM) by collecting the particles on TEM grids put on each stage of a cascade impactor.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.190-194
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• 2010

화재감지기는 화재시 발생되는 열, 연기, 불꽃, 독성가스등의 다양한 연소생성물을 감시한다. 기술의 발전으로 화재 감지방식과 기능이 다양해지고 있으며, 이에 따라 다양한 방식의 감지기들이 개발되고 있다. 최근 진보된 감지기들은 화재로 발생 이전에서 부터 감지, 비화재보에 대한 방지는 물론 감지기의 상태 오염 감도 등의 다양 정보를 제공함으로써 유사시 신속하고 정확한 대응이 가능하도록 발전되고 있다. 이러한 진보된 감지기는 막대한 피해가 예상되는 장소, 대피하는데 많은 시간이 소요되는 장소에 적용되어 인명 및 재산피해를 절감 시키고 있다. 일산화탄소감지기 또한 진보된 감지기로 화재 초기 가연물이 연소할 때 발생하는 일산화탄소를 감시한다. 일반화재의 경우 화재 초기에 가연물이 서서히 연소시 불완전 연소로 인한 다량의 일산화탄소가 발생되기 때문에 기존 열, 연기, 불꽃감지기에 비해 빠른 반응을 보여 화재를 조기에 감지함으로써 조기 대응으로 인한 피해를 줄일 수 있을 것이다. 본 연구에서는 실물화재시험 자료를 바탕으로 CO감지기의 조기 감시능력을 확인하였다. CO감지기는 화재초기 발생되는 일산화탄소를 감지하므로 대피시간이 많이 필요한 장소(병원 노인요양시설 학교 백화점 등), 침대 폼메트리스 훈소화재 발생장소(호텔침실 기숙사 숙박업소, 병실 등)등에 적응성이 우수할 것으로 분석된다. 최근 설계되는 초고층 건축물 및 주요 시설물 등에서 화재 시뮬레이션과 가상시나리오 유형 분석을 통해 성능위주의 설계가 적용되고 있다. 그만큼 정확하고 신속한 감지가 중요하다 할 수 있다. CO감지기야 말로 그 기대에 가장 부합될 것으로 분석된다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.475-478
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• 2005

Ducted rocket produces thrust by 2 steps, primary incomplete combustion in the gas generator, and secondary complete combustion reaction in combustion chamber mixed by air taken through duct. the range of a rocket is determined by the weight of propellant, especially the weight of fuel. So ducted rocket has more efficiency and high terminal speed compared to traditional solid rocket motor. This propulsion system expected to be applied to various kinds of missile for anti-aircraft, anti-ship

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.401-406
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• 2020

NOx (nitrogen oxide) in the exhaust gas engines causes severe air pollution. NOx is produced under high-temperature combustion conditions. EGR (exhaust gas recirculation) is normally used to reduce the combustion temperature and NOx production. As the EGR ratio increases, the NOx level becomes low. On the other hand, an excessively high EGR ratio makes the combustion unstable resulting in other air pollution problems, such as unburned hydrocarbon and higher CO levels. In this study, the improvement of fuel droplets moving by the radiation of sonic waves was studied for the stable combustion using analytic and experimental methods. For the analytical study, the effects of the radiation of a sonic wave on the fuel droplet velocity were studied using Fluent software. The results showed that the small droplet velocity increased more under high-frequency sonic wave conditions, and the large droplet velocity increased more under low-frequency sonic wave conditions. For the experimental study, the combustion chamber was made to measure the combustion pressure under the sonic wave effect. The measured pressure was used to calculate the heat release rate in the combustion chamber. With the heat release rate data, the heat release rate increased during the initial combustion process under low-frequency sonic wave conditions.

• Journal of the Korean Institute of Gas
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• v.27 no.1
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• pp.1-12
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• 2023

Coal gasification is a process of incomplete coal combustion to produce a syngas composed of hydrogen and carbon monoxide. It is one of methods to utilize coal cleanly because the process does not emits nitrogen oxides or sulfur oxides and particulate matters. In addition, chemicals can be produced using syngas. Coal gasification is classified as IGCC (Integrated Gasification Combined Cycle), Plasma coal gasification and UCG (Underground Coal Gasification). Recently, WGS (Water Gas Shift) reactor and carbon capture system have been combined to gasifier to produce hydrogen from coal. In this study, the coal gasification and method of hydrogen production from syngas was summarized, and the hydrogen production from coal gasification project was investigated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.8
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• pp.639-648
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• 2013

This paper describes on the NOx/CO emission characteristics, temperature characteristics and flame structures when firing coal derived synthetic gas especially for gases of Buggenum and Taean IGCC. These combustion characteristics were observed by conducting ambient-pressure elevated-temperature combustion tests in GE7EA model combustor when varying heat input and nitrogen dilution ratio. Nitrogen addition caused decrement in adiabatic flame temperature, thus resulting in the NOx reduction. At low heat input condition, nitrogen dilution raised the CO emission dramatically due to incomplete combustion. These NOx reduction and CO arising phenomena were observed at certain flame temperature of $1500^{\circ}C$ and $1250^{\circ}C$, respectively. As increasing nitrogen dilution, adiabatic flame temperature and combustor liner temperature were decreased and singular points were detected due to change in flame structure such as flame lifting. From the results, the effect of nitrogen dilution on the NOx/CO and flame structure was examined, and the test data will be utilized as a reference to achieve optimal operating condition of the Taean IGCC demonstration plant.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.502-509
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• 2013

To estimate greenhouse gas (GHG) emission, we established inventory of conventional rice cultivation from farmers in Gunsan and Iksan, Jeonbuk province in 2011~2012. This study was to calculate carbon footprint and to analyse the major factor of GHGs. We carried out a sensitivity analysis using the analyzed main factors of GHGs and estimated the mitigation potential of GHGs. Also we tried to suggest agricultural methods to reduce GHGs that farmers of this case study can apply. Carbon footprint of rice production unit of 1 kg was 2.21 kg $CO_2.-eq.kg^{-1}$. Although amount of $CO_2$ emissions is largest among GHGs, methane had the highest contribution of carbon footprint on rice production system after methane was converted to carbon dioxide equivalent ($CO_2$-eq.) multiplied by the global warming potential (GWP). Source of $CO_2$ in the cultivation of rice farming is incomplete combustion of fossil fuels used by agricultural machinery. Most of the $CH_4$ emitted during rice cultivation and major factor of $CH_4$ emission is flooded paddy field in anaerobic condition. Most of the $N_2O$ emitted from rice cultivation process and major sources of $N_2O$ emission is application of fertilizer such as compound fertilizer, urea, orgainc fertilizer, etc. As a result of sensitivity analysis due to the variation in energy consumption, diesel had the highest sensitivity among the energies inputs. If diesel consumption is reduced by 10%, it could be estimated that $CO_2$ potential reduction is about 2.5%. When application rate of compound fertilizer reduces by 10%, the potential reduction is calculated to be approximately 1% for $CO_2$ and approximately 1.8% for $N_2O$. When drainage duration is decreased until 10 days, methane emissions is reduced by approximately 4.5%. That is to say drainage days, tillage, and reducing diesel consumption were the main sources having the largest effect of GHG reduction due to changing amount of inputs. Accordingly, proposed methods to decrease GHG emissions were no-tillage, midsummer drainage, etc.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1972.03a
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• pp.6-7
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• 1972

The air pollutants can be classified into the irritant gas and the asphixation gas, and the irritant gas is closely related to the otorhinolaryngological diseases. The common irritant gases are nitrogen oxides, sulfur oxides, hydrogen carbon compounds, and the potent and irritating PAN (peroxy acyl nitrate) which is secondarily liberated from photosynthesis. Those gases adhers to the mucous membrane to result in ulceration and secondary infection due to their potent oxidizing power. 1. Sulfur dioxide gas Sulfur dioxide gas has the typical characteristics of the air pollutants. Because of its high solubility it gets easily absorbed in the respiratory tract, when the symptoms and signs by irritation become manifested initially and later the resistance in the respiratory tract brings central about pulmonary edema and respiratory paralysis of origin. Chronic exposure to the gas leads to rhinitis, pharyngitis, laryngitis, and olfactory or gustatory disturbances. 2. Carbon monoxide Toxicity of carbon monoxide is due to its deprivation of the oxygen carrying capacity of the hemoglobin. The degree of the carbon monoxide intoxication varies according to its concentration and the duration of inhalation. It starts with headache, vertigo, nausea, vomiting and tinnitus, which can progress to respiratory difficulty, muscular laxity, syncope, and coma leading to death. 3. Nitrogen dioxide Nitrogen dioxide causes respiratory disturbances by formation of methemoglobin. In acute poisoning, it can cause pulmonary congestion, pulmonary edema, bronchitis, and pneumonia due to its strong irritation on the eyes and the nose. In chronic poisoning, it causes chronic pulmonary fibrosis and pulmonary edema. 4. Ozone It has offending irritating odor, and causes dryness of na sopharyngolaryngeal mucosa, headache and depressed pulmonary function which may eventually lead to pulmonary congestion or edema. 5. Smog The most outstanding incident of the smog occurred in London from December 5 through 8, 1952, because of which the mortality of the respiratory diseases increased fourfold. The smog was thought to be due to the smoke produced by incomplete combustion and its byproduct the sulfur oxides, and the dust was thought to play the secondary role. In new sense, hazardous is the photochemical smog which is produced by combination of light energy and the hydrocarbons and oxidant in the air. The Yonsei University Institute for Environmental :pollution Research launched a project to determine the relationship between the pollution and the medical, ophthalmological and rhinopharyngological disorders. The students (469) of the "S" Technical School in the most heavily polluted area in Pusan (Uham Dong district) were compared with those (345) of "K" High School in the less polluted area. The investigated group had those with subjective symptoms twice as much as the control group, 22.6% (106) in investigated group and 11.3% (39) in the control group. Among those symptomatic students of the investigated group. There were 29 with respiratory symptoms (29%), 22 with eye symptoms (21%), 50 with stuffy nose and rhinorrhea (47%), and 5 with sore thorat (5%), which revealed that more than half the students (52%) had subjective symptoms of the rhinopharyngological aspects. Physical examination revealed that the investigated group had more number of students with signs than those of the control group by 10%, 180 (38.4%) versus 99 (28.8%). Among the preceding 180 students of the investigated group, there were 8 with eye diseases (44%), 1 with respiratory disease (0.6%), 97 with rhinitis (54%), and 74 with pharyngotonsillitis (41%) which means that 95% of them had rharygoical diseases. The preceding data revealed that the otolaryngological diseases are conspicuously outnumbered in the heavily polluted area, and that there must be very close relationship between the air pollution and the otolaryngological diseases, and the anti-pollution measure is urgently needed.