• 한국화재소방학회논문지
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• 제25권5호
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• pp.128-133
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• 2011

본 연구는 구획공간화재에서 화재특성과 위치에 따른 공간내부의 열유속 특성을 파악하기 위해 ISO-9705 표준화재실의 40 % 크기로 축소된 공간에서 화재 실험을 수행하였다. 열유속의 측정은 Schimit-Boelter type 열유속계를 이용하였으며 화재실의 내부와 출입구쪽의 중앙바닥면에서 열유속이 각각 측정되었다. 실험에 사용된 연료는 천연가스, 헵탄, 톨루엔, 에탄올, 폴리스틸렌 등이다. 실험결과 화재발열량과 상층부의 온도가 증가함에 따라 화재실 내부 바닥에서의 열유속이 출입구쪽에 비해 상대적으로 높게 나타났다. 또한 그을음의 생성이 많은 연료일수록 화재실 바닥면에서 열유속의 공간적인 편차가 상대적으로 크게 나타났다. 본 연구를 통해 공간내 하층부에서의 열유속 분포는 화재가 성장함에 따라 화염 및 상층부에서 방출되는 복사열과 밀접한 관계가 있고 이는 상층부의 온도뿐만 아니라 연소가스의 조성이나 그을음 농도(soot concentration), 환기조건 등과 같은 화재특성에 크게 영향을 받는다는 사실을 파악하였다.

• Journal of Mechanical Science and Technology
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• 제16권11호
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• pp.1550-1557
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• 2002

Diode laser sensor for measuring gas temperature and species concentration in combustion chamber was developed using 2.0 tim distributed feed back lasers. To evaluate the measurement sensitivity of diode laser sensor system, CO2 survey spectra near 2.0 Um were measured and compared with the calculated one. This diode laser absorption sensor was applied to measure gas temperatures in a premixed flat flame of CH$_4$-air mixture. Experimental results were in good agreement with the values by an R-type thermocouple within 6.12%. In addition, successful demonstration of measurement of gas temperature and species concentration in a soot flame showed the promising possibility of diode laser absorption sensors for practical combustion system with non-intrusive method.

• 설비공학논문집
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• 제13권5호
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• pp.321-332
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• 2001

In this study, a design program for ventilation requirements of a longitudinal raod tunnel were developed and investigated. The control volume method was applied to calculate the local air velocity and the local concentration distribution of pollutants, CO, $NO_x$, soot along the tunnel for various tunnel ventilation system. This program was validated by comparing with the practical design data for the road tunnel ventilation system. The calculation results were in good agreement with the practical design data.

• 수산해양기술연구
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• 제19권1호
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• pp.40-45
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• 1983

전자식전발분사노즐로 급속압축장치 내에서 실현한 축대칭 자유분무.화염에 고속도 사진의 화상해석을 적용하여 다음과 같은 결론을 얻었다. 1. 고속도 사진의 화상해석에 의해 구한 디이젤분무의 축방향의 연료농도분포는 분무의 선단부를 제외하면 준정상이론에 의한 분포와 정성적으로 일치한다. 2. 화염중심축방향의 그을음 농도는 연과의 농도가 비교적 낮은 분무의 선단부에서 높은 농도를 나타내며, 그 농도는 거의 분사종료시에 최대로 되어, 그 후 시간경과에 따라 저하한다. 3. 양파모델을 축대칭 분무.화염에 적용하여 분무.화염내부의 반경방향의 그을음 농도와 연료농도분포를 비교해 보면 그을음 농도의 가장 높은 부분은 연료농도가 가장 높은 중심부보다 화염반경의 2/3의 위치에서 최대로 되었다

• 해양환경안전학회지
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• 제19권5호
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• pp.518-524
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• 2013

본 연구에서는 균질기에 의해 혼합된 물과 벙커-A를 보일러로 연소하였을 때의 배기 배출물 특성에 대해 연구를 수행하였다. 그 결과로 균질기로 균질화 된 벙커-A의 경우, 순수 벙커-A에 비해 NOx 농도는 19 %, CO 농도는 54 % 감소를 나타냈다. 물-벙커A의 경우 물 혼합 비율이 증가할수록 NOx 농도분포가 낮아지는 것을 확인할 수 있었다. 특히, 20 %물-80 %벙커-A의 경우 순수한 벙커-A 보다 배기가스 내 NOx 농도가 45 %까지 감소하였다. 그러나 20 %물-80 %벙커-A의 경우, CO농도 분포는 불규칙한 변화를 나타냈다. 이것은 일정량 이상의 물 혼합은 보일러의 연소 성능 저하 원인이 될 수 있다는 것을 의미한다. 이 결과로부터 본 연구에서 보일러의 정상 연소를 위한벙커A유 내 물의 한계 혼합율은 15 % 인 것을 알 수 있었다. 연돌 부근에서 채취한 매연 부착양은 물의 혼합율이 증가할수록 감소하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제33권6호
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• pp.896-902
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• 2009

EGR is applied in order to lower temperature of combustion chamber by using the specific heat of carbon dioxide in engine exhaust gas. However, the problem of EGR system in diesel engine is high PM concentration. Combined EGR system can be reduced it by mixing exhaust gas of gas engine into the intake air of diesel engine. This experimental study was designed for EGR system for both engines use. The results of EGR experimental study by using diesel engine and gas engine are as follows. 1) The pressure of combustion and rate of heat release decreased. 2) The specific fuel consumption increased. But, up to middle load, it little increased. 3) NO concentration has decreased up to 50% in almost all combustion area. 4) The variation of the PM concentration at low load is not so seen. But at high load, PM increased rapidly when concentration of oxygen is decreased and most of it caused the increasing of Dry Soot.

• 한국환경과학회지
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• 제13권7호
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• pp.619-626
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• 2004

We have studied the catalytic combustion of soot particulates over perovskite-type oxides prepared by malic acid method, The catalysts were modified to enhance the activity by substitution of metal into A or B site of perovskite oxide. In addition, the reaction conditions such as temperature and $O_2$ concentration were investigated. The partial substitution of alkali metals into A site in the $LaMnO_3$ catalyst, enhanced the catalytic activity in the combustion of carbon particulate and the activity was shown in the order: Cs > K > Na. For the $La_{1-x}Cs_{x}MnO_{3}$ catalysts, the catalytic activity showed the maximum value with x=0.3 but no more increase on the catalytic activity was shown with x > 0.3. For the $La_{0.8}Cs_{0.2}MnO_{3}$ catalyst, the substitution of Fe or Ni increased the ignition temperature. The ignition temperature decreased with an increase of $O_2$ concentration, however, no more increase in the catalytic activity was shown with $O_2$ concentration > 0.2. The introduction of NO into reactants showed no effect on the catalytic activity.

• Asian Journal of Atmospheric Environment
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• 제11권2호
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• pp.79-95
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• 2017

A number of field studies have provided evidence that biomass burning is one of the major global sources of atmospheric particles. In this study, we have collected $PM_{2.5}$ emitted from biomass burning combusted at open burning and laboratory chamber situations. The open burning experiment was conducted with the cooperation of 9 farmers in Chiba Prefecture, Japan, while the chamber experiment was designed to evaluate the characteristics of chemical components among 14 different plant species. The analyzed categories were $PM_{2.5}$ mass concentration, organic carbon (OC), elemental carbon (EC), ionic components ($Na^+$, ${NH_4}^+$, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $Cl^-$, ${NO_3}^-$ and ${SO_4}^{2-}$), water-soluble organic carbon (WSOC), water-insoluble inorganic carbon (WIOC), char-EC and soot-EC. OC was the dominant chemical component, accounting for the major fraction of primary $PM_{2.5}$ derived from biomass burning, followed by EC. Ionic components contributed a small portion of $PM_{2.5}$, as well as that of $K^+$. In some cases, $K^+$ is used as biomass burning tracer; however, the observations obtained in this study suggest that $K^+$ may not always be suitable as a tracer for biomass burning emissions. Also, the results of all the samples tested indicate relatively low values of char-EC compared to soot-EC. From our results, careful consideration should be given to the usage of $K^+$ and char-EC as indicators of biomass burning. The calculated ratios of WSOC/OC and WIOC/OC were 55.7% and 44.3% on average for all samples, which showed no large difference between them. The organic materials to OC ratio, which is often used for chemical mass closure model, was roughly estimated by two independent methods, resulting in a factor of 1.7 for biomass burning emissions.

• 한국세라믹학회지
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• 제34권6호
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• pp.636-644
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• 1997

The effect of various processing parameters, in particular the substrate and filament temperature, on the nucleation of diamond has been studied for the hot filament CVD process with a negative bias on the substrate. As far as the substrate temperature was maintained around the critical temperature of 73$0^{\circ}C$, the nucleation of diamond increased with increasing filament temperature. The maximum nucleation density of ~ 2$\times$109/$\textrm{cm}^2$ was obtained under the condition of filament temperature of 230$0^{\circ}C$, substrate temperature of 75$0^{\circ}C$, bias voltage of 300V, methane concentration of 20%, and deposition time of 2 hours. This nucleation density is about the same as those obtained in previous investigations. For fixed substrate temperatures, the nucleation density varies up to about 103 times depending on experimental conditions. This result is different from that of Reinke, et al. When the substrate temperature was above 80$0^{\circ}C$, a silkworm~shaped carbon phase was co-deposited with hemispherical microcrystalline diamond, and its amount increased with increasing substrate temperature. The Raman spectrum of the silkworm-shaped carbon was the same as that of graphitic soot. The silkworm-shaped carbon was etched and disappeared under the same as that of graphitic soot. The silkworm-shaped carbon was etched and disappeared under the deposition condition of diamond, implying that it did not affect the nucleation of diamond.

• 한국자동차공학회논문집
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• 제14권3호
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• pp.95-102
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• 2006

Recently particulate matter(PM) emission regulations are becoming more strict for diesel engines. There is increasing interest for measuring not only concentration but also size of the particles. Laser-induced incandescence (LII) has emerged as a promising technique for measuring particle volume fraction and size. In this study, the Simple Time Resolved-LII method was applied to exhaust of Ethylene diffusion flame and diesel engine exhaust for measuring soot and PM size. The particle size data from LII technique were calibrated using Field Emission Scanning Electron Microscope(FE-SEM) and Transmission Electron Microscope(TEM) photographs. In diesel engine experiments for particle size measurement, results from LII measurement are in a good agreement with those from TEM photograph, and difference between two measurements was less than 16%.