• Journal of the Korean Wood Science and Technology
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• 제30권3호
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• pp.18-25
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• 2002

Research to discuss the fire performance of materials requires tools for measuring their burning characteristics and validated fire growth models to predict fire behavior of the materials under specific tire scenarios using the measured properties as input for the models. In this study, burning characteristics such as time to ignition, weight loss rate, flame spread, heat release rate, total heat evolved, and effective heat of combustion for four types of wood-based materials were evaluated using the cone calorimeter and inclined panel tests. Time to ignition was affected by not only surface condition and specific gravity of the tested materials but also the type and magnitude of heat source. Results of weight loss rate, measured by inclined panel tests, indicated that heat transfer from the contacted flame used as the heat source into the inner part of the specimen was inversely proportional to specific gravity of material. Flame spread was closely related with ignition time at the near part of burning zone. Under constant and severe external heat flux, there was little difference in weight loss rate and total heat evolved between four types of wood-based panels. More applied heat flux caused by longer ignition time induced a higher first peak value of heat release rate. Burning characteristics data measured in this study can be used effectively as input for fire growth models to predict the fire behavior of materials under specific fire scenarios.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1997년도 International Symposium on Fire Science and Technology
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• pp.162-168
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• 1997

A theoretical model for the interaction of the moving heat source and a solid substrate when they are in contact is described. for purposes of the model the substrate is assumed to act as a continuum and the Fourier equation for transient. three-dimensional conduction is solved using Laplace and Fourier transformations. Unlike most previous models, this model shows the explicit relations between the properties of heat source and that of the substrate. Since the size, shape and speed of heat source impact the ignition of substrate, considerable attention is devoted to evaluating these parameters. Results are presented which show the effects of the size, shape and speed of heat source on the substrate.

• 한국화재조사학회학술대회
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• 한국화재조사학회 2011년도 제21회 춘계학술대회
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• pp.102-116
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• 2011

구제역 및 AI의 확산으로 전국의 많은 축산농가에 보급되어 있는 생석회(CaO)의 보관방법 잘못으로 인하여 생석회가 화재의 발화원으로 작용한 사례가 다수 존재한다. 화학적으로 생석회가 물과 결합시 발열 한다. 그렇다면 이 발열량이 어떠한 환경과 조건에서 발화원으로 작용하는 것인지 실험을 통하여 알고자 하였다. 이에 인위적으로 형성한 실험조건에서 생석회와 물과의 결합시 발열여부를 확인하고, 발화에 이르는 온도변화 및 발화과정을 실험해 보았다. 그 결과 적당한 수분과 축열조건, 그리고 가연물의 존재가 전제된다면 생석회가 발화원으로 작용할 수 있는 충분한 가능성을 확인하였다. 생석회가 발화원으로 작용한 화재현장의 감식기법으로는 우선 생석회 주변에 물과 가연물질의 존재여부 확인 및 발화장소에서의 수산화칼슘($Ca(OH)_2$)의 존재여부를 확인하는 것이 우선되어야 한다. 이와 같은 실험결과를 바탕으로 제조업체나 농협, 축산농어민 등 제품취급에 관련된 사람에 대한 안전취급 교육을 확행하여 화재를 미연에 방지할 수 있도록 하여야 한다.

• 대한기계학회논문집B
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• 제20권11호
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• pp.3630-3638
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• 1996

An experimental study has been conducted to explore the behaviors of the radiative ignition of polymethylmetacrylate(PMMA) in a confined enclosure such as the ignition delay time, PMMA surface temperature, the ignition location and the ignition process. In addition, the effects of hot wall orientation on the ignition delay and PMMA surface temperature were studied. When the hot wall is located at the bottom, ignition delay time is the shortest. Ignition surface temperature becomes the lowest for the hot top wall case. These are due to buoyancy effect. Since the radiative heat flux of hot wall is rather lower than laser source, the ignition is considered to be controlled by the mixing process. Therefore, the ignition location, where appropriate mixture of fuel and oxygen exists, occurs near the hot wall. The flame propagates along the hot wall where there exists sufficient oxygen.

• 한국안전학회지
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• 제31권2호
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• pp.18-25
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• 2016

The incandescent lamp is an electric light fixture with a tungsten filament heated to a high temperature, by passing an electric current through it, until it glows with visible light. The hot filament is protected from oxidation with a glass bulb that is filled with inert gas. The incandescent lamp has fire risk when combustible materials are close to its glass bulb. Because its lamp has the property which converts 90~95 percents of the electric power to heat energy. 2015 national fire statistics show that fires caused by lighting fixtures were 652 cases, and incandescent lamps(44 cases) and halogen lamps(53 cases) accounted for 15 percents in those of high heating light fixtures. Since incandescent lamp fires account for about 45 percents in the high heating light fixture, we could not overlook the fire risks by the incandescent lamp. Although many studies related with those have been conducted, incandescent lamp fires are continuously occurred. This study was carried out to study the fire risk of ignition of wood due to radiant heat of incandescent lamp. Radiant heat flux of the incandescent lamp was predicted by applying point source model, and critical distance for ignition of wood was calculated by applying integral model. The results from this study could applied to fire prevention activities related to light bulb, and it could be used in fire cause investigations related to radiant heat of incandescent lamp.

• 대한기계학회논문집
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• 제19권12호
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• pp.3352-3359
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• 1995

An Eulerian-Lagrangian method is employed to simulate the ignition process and the flame propagation through the air/fuel spray mixture in a closed constant-volume combustor. The spray mixture is ignited by providing a hot wall at the end of the combustor or by firing the electric spark. The investigated parameters involve the initial droplet size, overall equivalence ratio, initial fuel vapor concentration, distance between the hot wall and the nearest droplet, and the ignition energy. Numerical results clearly show the existence of the optimum spray condition for minimizing the ignition energy and the ignition delay time as well as the critical dependence of ignition upon the distance of the heat source to the nearest droplet.

• 대한기계학회논문집
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• 제19권9호
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• pp.2353-2364
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• 1995

The ignition phenomena of a solid fuel plate of polymethyl-methacrylate(PMMA), which is vertically positioned and exposed to a thermal radiation source, is numerically studied here. A two-dimensional transient model includes such various aspects as thermal decomposition of PMMA, gas phase radiation absorption, gas phase chemical reaction and air entrainment by natural convection. Whereas the previous studies considers the problem approximately in a one-dimensional form by neglecting the natural convection, the present model takes account of the two-dimensional effect of radiation and air entrainment. The inert heating of the solid fuel is also taken into consideration. Radiative heat transfer is incorporated by th Discrete Ordinates Method(DOM) with the absorption coefficient evaluated using gas species concentration. The thermal history of the solid fuel plate shows a good agreement compared with experimental results. Despite of induced natural convective flow that induces heat loss from the fuel surface, the locally absorbed radiant energy, which is converted to the internal energy, is found to play an important role in the onset of gas phase ignition. The ignition is considered to occur when the rate of variation of gas phase reaction rate reaches its maximum value. Once the ignition takes place, the flame propagates downward.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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• pp.122-125
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• 2003

For Lab-scale Hybrid Rocket's Ignition, It is needs of heat source to vaporize solid fuel. We used Nichrome wire which has a electric resistance for ignition. But Ignition system by using Nichrome wire is not only the disposable system, but also the system which has an affect on the Hybrid rocket's structures(nozzle throat diameter). The new Ignition system composed of Butane+propane gas' supply devices and spark plug. RPL(Rocket Propulsion Lab.) perform the hybrid rocket experiments over 50 times by using new ignition system. The fact that is possible to throttle the Thrust in hybrid rocket is confirmed.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제25회 KOSCI SYMPOSIUM 논문집
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• pp.25-31
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• 2002

For the better understanding of the stability of turbulent combustion, more researches on extinction and re-ignition are needed. Flame interactions in non-premixed flame have also not been greatly researched. We made a hybrid twin jet flame, the combinations of diffusion flame and partially-premixed diffusion flame, in a twin jet counterflow configuration. The extinction limits of a crossed twin jet counterflow have been extended in comparison with those of a one-dimensional counterflow because of flame interactions through heat transfer and joint ownership of various radicals. Besides, we have obtain ignition $Damk\"{o}hler$ number by experimental method without external ignition source using the extinction characteristic in a crossed twin jet counterflow flame. From results, we can identify the hysteresis between extinction and ignition $Damk\"{o}hler$ number in S-curve.

• International Journal of Automotive Technology
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• 제5권3호
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• pp.195-200
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• 2004

This paper is concerned with the Homogeneous Charge Compression Ignition (HCCI) engine as a new concept in engines and a power source for future automotive applications. Essentially a combination of spark ignition and compression ignition engines, the HCCI engine exhibits low NOx and Particulate Matter (PM) emissions as well as high efficiency under part load. The objective of this research is to determine the effects of Exhaust Gas Recirculation (EGR) rate on the combustion processes of HCCI. For this purpose, a 4-cylinder, compression ignition engine was converted into a HCCI engine, and a heating device was installed to raise the temperature of the intake air and also to make it more consistent. In addition, a pressure sensor was inserted into each of the cylinders to investigate the differences in characteristics among the cylinders.