• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.63-63
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• 2011

화재란 사람의 의도에 반하거나 고의에 의해 발생하는 연소현상으로서 소화시설 등을 사용하여 소화할 필요가 있는 것을 말한다. 사람의 의도에 반한다고 하는 것은 과실에 의한 화재를 의미하며 화기취급 중 발생하는 실화뿐만 아니라 부작위에 의한 자연발화도 포함하며, 고의에 의한다고 하는 것은 일정한 대상에 대하여 피해발생을 목적으로 화재발생을 유도하였거나 직접 방화한 경우를 말한다. 연소현상이라 함은 가연성 물질이 산소와 결합하여 열과 빛을 내며 급속히 산화되어 형질이 변경되는 화학반응을 말한다. 소화시설 등을 사용하여 소화할 필요가 있다는 것은 화재란 연소현상으로서 소화의 필요성이 있어야 하며 소화의 필요성의 정도는 소화시설이나 그와 유사한 정도의 시설을 사용할 수준 이상이어야 한다. 화재원인조사란 발화부를 판단하고 화재에 이르게 된 발화원을 규명하며, 발화부로부터 연소확대된 경과를 조사하는 일련의 행위로서 화재원인조사시 가장 중요한 사항은 발화부 판단인 바, 이는 화재원인이 발화부에만 존재하기 때문이다. 최근에는 다양한 소재의 사용으로 인해 일단 화재로 진행될 경우 인명 및 재산상 피해가 증가하게 되어 있으며, 이로 인해 화재조사시 화학, 물리, 전기, 건축, 기계, 소방 등 다양한 지식과 화재현장에 대한 이해가 요구된다. 화재현장 조사시 발화부 판단의 과학적 접근은 매우 중요한 것으로서, 화재원인의 명쾌한 규명으로 책임한계 구분은 물론, 유사사고의 재발방지를 위한 연구가 필요하다. 본 연구에서는 기 발생한 화재사례에서 얻은 화재패턴을 분석하여 얻은 자료를 통해 발화부를 판단할 수 있는 조사방법을 다음과 같이 제시하였다. 1) 화재시 열전달과 화염확산 과정에서 건축구조물, 내장재, 집적물 및 각종 설치물의 구조, 재질 등에 따라 다양한 화재패턴을 형성하게 됨을 알 수 있다. 2) 화재패턴의 종류로는 화재플럼에 의한 삼각형, 주상, V, U 패턴 등이 있으며, 연소 생성물인 화염, 연기, 열 등에 의해 다양한 형태를 보임을 알 수 있다. 3) 위와 같은 결과를 종합하여 연소의 상승성, 불꽃 및 연기 흔적, 열에 의한 흔적 등에 의해 연소의 방향성을 알 수 있다. 4) 결국 화재현장에서 명확한 화재원인을 규명하기 위해서는 화재패턴에 의해 연소확대과정을 역으로 추적하여 발화부를 결정한 다음, 발화부내에서 화재원인을 찾아내야 할 것이다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2008.04a
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• pp.161-166
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• 2008

This paper searched through mixture ratio response test whether exert effect that is some in part load performance of engine according to inlet valve angle in gasoline engine. Engines that inlet valve angle is narrow decreased quantity of NOx among exhaust gas than engine that inlet valve angle is wide, and ignition timing was retard, and fuel consumption improved a little. That quantity of NOx among exhaust gas decreases and ignition timing was retard can judge that fast burning occurred. Fast burning can decrease output decline and misfire that can happen at lean burning. Can be judged by thing which engine's combustion performance improves if inlet valve angle is narrow if examine test result.

• Fire Science and Engineering
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• v.25 no.3
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• pp.20-27
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• 2011

This paper studied combustion characteristics of the sponge type sound-absorbing materials extensively used on building interior. To estimate of the combustion characteristics, we carried out combustion experiment of general type and incombustibility type sound-absorbing materials. And then to evaluate the suitability of the sponge type sound-absorbing materials, we measured heat release rate (HRR) and smoke density (Ds) of the sound-absorbing materials using by a cone-calorimeter. From the combustion experimental results, general type sound-absorbing materials were rapid burned simultaneously with ignition and the incombustibility type sound-absorbing materials had all gone out simultaneously with ignition. Measured results of HRR and Ds were not satisfied KS F ISO 5660-1 and IMO FTP Code, form the results, the sponge type sound-absorbing materials were ill-suited for using building interior.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.12
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• pp.1035-1042
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• 2010

The thermal stratification effect has been thought as one of the way to avoid dramatically generating the heat from HCCI combustion. We investigate the effect of thermal stratification on HCCI combustion fueled by DME and n-Butane. The thermal stratification occurs in a combustion chamber of a rapid compression machine with premixture by buoyancy effect that is made of fuel and air. The premixture is then adiabatically compressed, and during the process, the in-cylinder gas pressure is measured and two-dimensional chemiluminescence images are prepared and analyzed. Under the thermal stratification, the LTR starting time and the HTR starting time are advanced than that of homogeneous case. Further, the LTR period and the luminosity duration under homogeneous conditions are shorter than the corresponding quantities under stratified conditions. Additionally, under stratified conditions, the brightest luminosity intensity is delayed longer than that of homogeneous condition.

• Journal of Energy Engineering
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• v.16 no.3
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• pp.120-127
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• 2007

The purpose of this study is experimentally to analyze that the fuel mass fractions of multi-component mixed fuels have an effect on the characteristics of spray ignition and combustion under the ambient conditions of diesel combustion fields. The characteristics of ignition and combustion were investigated by chemiluminescence images and direct photography. The experiments were conducted in the RCEM(rapid compression expansion machine) with optical access. Multi-component fuels mixed with i-octane, n-dodecane and n-hexadecane are injected in RCEM by the electronic control of common rail injector. Experimental conditions set up 42, 72 and 112 MPa in injection pressure, 700, 800 and 900 K in ambient gas temperature. The results show that the ignition delay was dependent on high cetane number. In case of low ambient temperature, the more low boiling point fuels were mixed, the lower luminance regime had a remarkable effect and also shortened diffusion combustion by increasing heat release rate.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.2
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• pp.83-90
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• 2004

A flywheel-driven rapid compression and expansion machine is developed and utilized for experimental study of homogeneous charge compression ignition combustion. Compression ignition of homogeneous charge in IC engines offers possibilities of realizing ultra-lean engine operation with greatly reduced NOx and particulate formation. Fundamental investigations are carried out in order to better understand this ideal engine combustion mechanism. Perfectly premixed propane-air mixtures of various equivalence ratio are compression-ignited in the rapid compression and expansion machine, and the characteristics of the auto-ignition and the following combustion process are analyzed.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.76-85
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• 1999

GDI(Gasoline Direct Injection( engine technology is well known as a new technology since it can improve fuel consumption and meet future emission regulations. But the GDI has many difficulties to be solved, such as complexity of injection control mode, unburned hydrocarbon, and restricted power. A 2-D shape combustion chamber was adopted to investigate mixture formation and combustion characteristics of GDI engine. Spray and combustion experiments were performed by changing the injection timing. injection pressure an din-cylinder flow in Rapid Compression and Expansion Machine(RCEM).Through the experiments, the detailed characteristics of fuel spray and combustion was analyzed by visualizing the in-cylinder phenomena according to the change of injection condition, and the optimal fuel injection timing and fuel injection pressure were obtained.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3329-3334
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• 2007

The purpose of the research is to investigate of diesel spray combustion for simultaneously reduce way NOx and PM. The pressure diesel injection were done into intermediates that are generated by very lean DME HCCI combustion using a RCM. The concentration of intermediate could not be directly measured; we estimated it by CHEMKIN calculation. DME HCCI characteristic is surveyed. Validations of the CHEMKIN calculation were confirmed pressure rise of an experiment and pressure rise of a calculation. Using a framing streak camera captured two dimensional spontaneous luminescence images from chemical species at low temperature reaction(LTR) and high temperature reaction (HTR). Also, the combustion events were observed by high-speed direct photography, the ignition and combustion were analyzed by the combustion chamber pressure profiles.

• Journal of the Korean Society of Combustion
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• v.9 no.4
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• pp.22-27
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• 2004

Lean premix combustion is a best method in low $NO_x$ gas turbine combustor and we must know the characteristics of NO emission in high temperature and pressure condition in premix flame. Numerical analysis was performed to investigate the NO emission characteristics by adopting a counterflow as a model problem using detailed chemical kinetics. Methane $(CH_4)$ was used as a test fuel which is the main fuel of natural gas. The tested parameters were stretch rate, equivalence ratio, initial temperature, and pressure in premix flame. Results showed that NO emission was high in low stretch rate, near stoichiometric equivalence ratio, high initial temperature, and high pressure. Also, the pressure effect was sensitive in high temperature condition.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.3
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• pp.80-89
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• 1992

An experimental study of in-cylinder of flow and combustion characteristics in two gasoline engines of different intake ports which are denoted as original port and masked shroud head (MSH) ports is presented. The flows generated by the MSH and the original port are invest- igated by laser Doppler velocimeter(LDV) under steady flow and motoring (non-firing) condit -ions. Combustion characteristics with different swirl levels produced by two intake ports are analyzed by combustion pressure measurement and statistical calculation. The swirl inside the cylinder of the MSH port engine is found to be much higher than the original port, and the MSH has a large eddy motion of cylinder diameter size. Using ensemble average method to valuate engine turbulence under motoring condition, the MSH port engine is shown to have h -igher turbulence intensity than the original port, so that the effect of the MSH port on fast burn is shown. Also the cyclic variations of peak pressure and the reaching time in the MSH port are apparently reduced.