• 대한기계학회논문집B
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• 제24권5호
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• pp.677-686
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• 2000

The characteristics of combustion and of emissions in pressurized fluidized bed combustor are investigated. The pressure of the combustor is fixed at 6 atm, and the combustion temperatures are set to 850, 900, and $950^{\circ}C$. The gas velocities are 0.9, 1.1, and 1.3 m/s. The excess air ratio is varied from 5 to 35%. The coal used in the experiment is Shenhwa coal in China. All experiments are executed at 2m bed height. Consequently, NOx & $N_2O$ concentration in the flue gas is increased with incresing excess air ratio but $SO_2$ concentration is decreased with incresing excess air ratio. CO concentration is maintained below 100ppm at over 15% of excess air ratio.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1997년도 International Symposium on Fire Science and Technology
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• pp.211-218
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• 1997

Five parts of vehicle upholsteries were sampled to determine its combustion characteristics. Oxygen Indexer, Smoke chamber, Differential Scanning Calorimetry(DSC) are applied as the analysis apparatus. All LOI values of samples appear less than 21. The combustion phenomena of vehicle upholster primarily depends on properties of each layer material. The amount of smoke generated is the experiment reached the maximum value within 30-90sec after ignition. The experimental results of combustion characteristics and DSC of H/Line also indicated that the layer of foam was melt first and it caused the propagation of flame through the sample. The combustion characteristics of multi layer materials primarily depend on thermal characteristic of single layer material.

• 대한기계학회논문집B
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• 제28권10호
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• pp.1172-1177
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• 2004

The emission control of automobile has been intensified as a part of the countermeasure to decrease air pollution in the world. As the cars with an alternative fuel starts to get into the spotlight, the cars with low emission has been introduced and exhaust gas regulation forced in this country. These days, LPG vehicles, which infrastructure of fuel was already built up, and CNG vehicles are recognized for alternative fuel cars in this country. In this study, the constant volume combustion chamber was manufactured and used for experiments to obtain the combustion characteristics of propane mixture. The combustion characteristics was analyzed, with the change of supply conditions of propane fuel. Inside the combustion chamber, the maximum temperature increase with the initial pressure is going up. The burning velocity also seems to have the same characteristic as the temperature. However, the heat flux do not change much according to the theoretical correct mixture but it changes with the various initial temperature of the combustion chamber.

• 한국자동차공학회논문집
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• 제5권4호
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• pp.70-83
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• 1997

We made a selection of engine operating conditions in the natural aspiration type diesel engine as load and speed. The effects on the power, smoke emission and cylinder pressure characteristics of these variations in operating conditions were observed experimentally. Also, the smoke emission was predicted by using the Arrhenius equation and empirical equation of the smoke emission was made. At the same time, the correlations, between the combustion and smoke emission characteristic were examined. From the above results, it is clear that to prevent power dropping and to decrease exhaust fume whin the conditions are changed, one should improve the intake system. To do this, the best way is to lower the air-fuel mixing ratio. We found that the parameters of the indicated mean effective pressure, maximum pressure and its location and combustion duration, etc. change the motion in accordance with the conditions described above. Also, we found that the variation of the pressure cycle comes from an amplified variation of the early part of process. From the analysis of comparing combustion and exhaust fume, the exhaust fume is produced at the latter time of combustion and decreased when the combustion ratio is higher. Also, we developed a special formula which can predict the exhaust fume value according to the engine load and speed.

• 화약ㆍ발파
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• 제18권1호
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• pp.53-58
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• 2000

Thermal analysis, analysis of combustion residue and combustion characteristics measure ment such as burning rate or temperature were carried out to clarify the combustion mechanism of a tungsten- potassium perchlorate-barium chromate chromate delay powder. The results obtained are as follows. The main reaction of the delay powder of tungsten-potassium perchlorate-barium chromate is the oxidation of tungsten by potassium perchlorate. Barium chromate acts as a burning rate modifier, and the smaller the larger is the burning rate. Three types of delay composition used in this study show characteristic burning behavior. A stoichiomertric or a oxidizer-rich composition has a small linear burning rate. although it is has a large heat of combustion. On the other hand, a tungsten-excess or a fuel-rich composition with a small heat of combustion has a larger linear burning rate than the former, showing a small fractional oxidation of tungeten (below 10%) contained in the delay powder. From these results, a surface combustion mechanism is proposed for the combustion mechanism of this delay powder.

• 한국자동차공학회논문집
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• 제14권2호
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• pp.49-56
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• 2006

The single droplet combustion characteristics of multicomponent fuel such as diesel-oxygenate and diesel-paraffin blends under high ambient temperature and atmospheric pressure were investigated in the study. The results of the study may be concluded as follows : In the combustion of diesel fuel droplet with additive of oxygenate and paraffin, the dimensionless droplet size of $(D/D_o)^2$ was linearly decreased with time. A fuel droplet with low boiling temperature additives and in high boiling temperature diesel fuel evaporates and burns faster than usual diesel fuel. This rapid burning may result from so-called "micro-explosion" and its burning intensity varies with the types of additives. The results above may suggest that rapid evaporation of oxygenate additive in the middle stage of combustion can contribute much to combustion improvement of blended fuels. When compared to ordinary diesel fuel, neat oxygenate and paraffin fuels show blue flame during entire combustion which prove smokeless combustion.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.325-329
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• 2017

본 연구에서는 탄화수소 계열 케로신 연료를 적용한 이중모드 램제트 연소기에 대하여 마하수 3.5~6.0 조건에서 연소시험을 수행하였다. 이릍 통해서 격리부, 상부(초음속)연소실 및 하부(아음속)연소실 내부의 온도와 압력분포를 측정하여 연소실 내부의 연소특성을 연구하였다. 마하수 3.5~5.0 까지는 아음속 연소 모드로서 하부 연소실에서 램연소를 확인할 수 있었으며, 마하수 6.0 조건에서는 인젝터에서 분사된 연료가 자연발화하여 상부 연소실에서 초음속 연소가 성공적으로 발생하였음을 확인할 수가 있었다.

• 대한기계학회논문집B
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• 제30권5호
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• pp.465-471
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• 2006

Controlled auto-ignition(CAI) combustion, offers the potential to improve fuel economy and reduce emission simultaneously. In this study, CAI-combustion was achieved in a single cylinder gasoline DI engine with modified camshafts in order to restrict the gas exchange process. We investigated the effects of air-fuel ratio, residual EGR rate and injection timing such as early injection and late injection on the attainable CAI combustion region. The effect of injection timings on combustion characteristic such as start of combustion, combustion duration and heat release rate was also investigated. From the result early injection causes the mixture to ignite earlier and burn more quickly due to the exothermic reaction during the recompression and gives rise to good mixing of the fuel/air. On the other hand, late injection extended the operation region more than early injection but the emissions of HC and NOx were more or less increased than early injection.

• 유기물자원화
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• 제22권1호
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• pp.11-19
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• 2014

본 연구에서는 건조 하수슬러지의 화석연료와의 혼소 가능성 평가를 연소특성, 경제적 이익 2가지 관점에서 평가하였다. 공업분석 결과 A하수처리장의 건조 하수슬러지의 휘발분은 36.48%, B하수처리장은 40.10%로 석탄에 비해 매우 높았으며, 연료비는 0.12, 0.14로 매우 낮아 연료로써의 품질은 낮은 것으로 조사되었다. 특히 연소성 지수가 30,000kcal/kg 이상으로 연료의 기준인 3,000~5,000kcal/kg을 크게 초과하여 건조 하수슬러지의 개질이 필요할 것으로 판단된다. 건조 하수슬러지의 경제성 평가 결과 석탄의 절감에 따른 이익은 연간 73.4억원, REC인증 이익은 56.4억원이 발생하는 것으로 산정되었다. 반면에 회분처리비용 증가에 따른 손실은 2.6억원, 건조 하수슬러지의 혼소에 소요되는 설비의 투자 및 운영비가 4.2억원으로 산정되어 건조 하수슬러지의 혼소에 따른 경제적 이익은 연간 123억원으로 추산되었다. 다만, 건조 하수슬러지의 생산에 소요되는 동력 및 건조 하수슬러지의 혼소로 인한 환경오염 등에 대한 비용은 본 연구에서 고려되지 못하였으며 향후 이에 대한 연구가 추가적으로 필요할 것이다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.137-142
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• 2001

The effects of acoustic excitation with various frequencies for combustion air as well as fuel on the combustion emission and local NO concentration in diffusion flame were investigated experimentally. It was studied to investigate the effects of combination between four frequencies for the fuel and various frequencies for the combustion air. The better characteristic for NO emission was revealed by acoustic exciting with frequencies for the air and the fuel excited at 0Hz and 120Hz and the generation of CO was decreased at low frequency for fuel and the excited combustion air. The amount of combustion emission could be controlled by acoustic exciting of the combustion air. And when both fuel and air are excited by some frequencies, the diffusion flame was affected by frequency which excited fuel in the middle of the flame and by air-exciting frequency at both sides of the flame. The local NO in the flame was generated much less at the condition that fuel was excited by frequencies than the condition was not.