• Bulletin of the Korean Chemical Society
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• 제21권10호
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• pp.957-958
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• 2000

The addition effect of $CH^3Br$ on the ignition of methane was investigated in the temperature range of 1537-1920 K behind reflected shock waves. The ignition delay times were measured by the sudden increase of pres-sure and OH emission in the $CH_4-O_2-Ar$ system containing small amount of $CH_3Br.$ The delay times of mix-tures with $CH_3Br$ were shorter than those without $CH_3Br.$ The promotion of ignition by $CH_3Br$ was caused by the relative fast decomposition rate in additive. To clarify the addition effect of $CH_3Br$ from the viewpoint of the reaction mechanism, computational analyses were performed in $CH_4-CH_3Br-O_2-Ar$ mixtures.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1249-1252
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• 2003

To analyse the cyclic variations in a test engine, the burn parameters are determined on a cycle-to-cycle basis through the analysis of the engine pressure data. Combustion analysis based on cylinder-pressure provides a mechanism through which a combustion researcher can understand the combustion process. The objective of this paper is to identify the most significant sources of cycle-to-cycle combustion variability in a spark ignition engine at idle. The burn rate analysis program was used and the burn parameters were used to determine the variations in the input parameter. In this study, the author investigated the relationship of indicated mean effective pressure, coefficient of variation of indicated mean effective pressure and burn angles, and lowest normalized value in a spark ignition engine for the cyclic variations.

• 한국안전학회지
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• 제26권1호
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• pp.21-26
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• 2011

Extinction and ignition characteristics of $CH_4$-air counterflow diffusion flame were numerically investigated using a Flame-Controlling Method(FCM). A skeletal reaction mechanism, which adopts 17 species and 58 reactions, was used in the simulation. The extinction and ignition conditions of the $CH_4$-air diffusion flames were investigated with varying the global strain rate. Upper and middle branches of S-curve for the peak temperature in the inverse of the global strain rate space were obtained with the FCM. The structures of diffusion flames in the upper and middle branches of S-curve were compared. It was found that the global strain rate was not correlated with the local strain rate well in the low global strain rate region. It is expected that the FCM is very useful to obtaining the extinction and ignition condition of diffusion flame, such as fires.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.309-310
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• 2012

Modeling of biodiesel combustion on compression ignition engine was conducted by using the KIVA3v-Release 2 code coupled with Chemkin chemistry solver2. In order to calculate the chemical kinetics of combustion of biodiesel, a reduced mechanism of methyl decanoate and methyl 9-decanoate was used. It is composed of 123 species and 394 reactions. Also, the experiments were performed on a single-cylinder engine. The simulation results agreed well with experiments results. And soot concentrations of biodiesel were lower than those of diesel.

• 대한화학회지
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• 제46권6호
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• pp.595-598
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• 2002

• 오토저널
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• 제6권2호
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• pp.47-54
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• 1984

The predictions of the mean effective pressure and the exhaust emission of NOx in hydrogen fueled spark ignition engine were studied. And the predictions were compared to the experimental results of D.B. Kittelson and H.S.Homan. The modeling was based on Otto cycle and the prediction of NOx was performed by extended Zeldovich mechanism. The differences between predictions and experimental results were 20 - 30% in the mean effective pressure and 10 - 20% in the concentration of NOx where the equivalence ratio .phi. was 0.6 - 0.8.

• Bulletin of the Korean Chemical Society
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• 제21권5호
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• pp.487-492
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• 2000

The combustion characteristics of a mixture of acetaldehyde, oxygen and argon behind a reflected shock wave at temperatures ranging from 1320 to 1897 K at 100 torr were studied. The emission from the OH radical at 306.4 nm and the pressure profile behind the reflected shock were measured to monitor ignition delay time. The ignition delay times were computed from a proposed mechanism of 110 elementary reactions involving 34 species. The simulation and sensitivity analysis confirm that the main channel for oxidation of acetaldehyde at high temperature consists of the Rice-herzfeld mechanism, the decomposition and oxidation of HCO, and the reaction of H with $O_2$.

• 한국안전학회지
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• 제26권5호
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• pp.118-129
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• 2011

In this study, species resistant to forest fire were extracted from high trees through an investigation of combustion mechanism. Here, the average flameless ignition temperatures of living leaves, branches and barks of oak were respectively, $365^{\circ}C$, $440^{\circ}C$ and $435^{\circ}C$, and the average flameless ignition temperatures of living leaves, branches, barks and cones of pine tree were respectively, $320^{\circ}C$, $405^{\circ}C$, $435^{\circ}C$ and $363^{\circ}C$. It shows that generally, pine tree has a lower flameless ignition temperature than oak and thus, has a relatively high risk of flameless ignition. When comparing risk of fire depending on ignition characteristics, Quercus serrata had a low risk of stem fire, and Quercus acutissima and Quercus serrata had a low risk of crown fire, as well. When analysing risk of fire depending on a duration of flame, also, Quercus dentata had a low risk of stem fire, and Quercus variabilis Blume had a low risk of crown fire too. Lastly, when comparing risk of fire, according to heat release rates, Quercus acutissima had a low risk of stem fire, and Quercus acutissima and Quercus dentata had a low risk of crown fire, as well. In conclusion, it was observed that as fire-resistant species, Quercus serrata and Quercus dentata have a low risk of ignition, Quercus variabilis Blume has a short duration of flame after discharging ignition when a forest fire occurs, and Quercus acutissima, Pinus Rigida and Antipathes japonica Brook have low heat release rates.

• 대한화학회지
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• 제43권2호
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• pp.156-160
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• 1999

메탄-산소를 아르곤으로 희석한 혼합기체의 점화 과정을 1516-1937K 온도 범위에서 반사 충격파를 이용하여 고찰하였다. 메탄 기체의 점화 지연 시간은 충격관 끝에서 5.0 cm 떨어진 곳에서의 압력 변화 및 광 방출을 측정하여 구하였으며, 각 혼합기체의 농도 의존도 및 온도 의존도에 관한 실험식을 구할 수 있었다. 메탄 산화 과정에 관한 실험 결과를 설명하기 위해 GRI 1.2 메카니즘을 이용한 컴퓨터 모의 실험을 수행하였다.

• Journal of Mechanical Science and Technology
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• 제14권10호
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• pp.1151-1158
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• 2000

Combustion analysis based on cylinder-pressure provides a mechanism through which a combustion researcher can understand the combustion process. The objective of this paper was to identify the most significant sources of cycle-to-cycle combustion variability in a spark ignition engine at idle. To analyse the cyclic variation in a test engine, the burn parameters are determined on a cycle-to-cycle basis through the analysis of the engine pressure data. The burn rate analysis program was used here and the burn parameters were used to determine the variations in the input parameter-i. e., fuel, air, and residual mass. In this study, we investigated the relationship of indicated mean effective pressure (IMEP), coefficient of variation (COV) of IMEP, burn angles, and lowest normalized value (LNV) in a spark ignition engine in a view of cyclic variations.