• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.147-150
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• 2015

When high-pressure gas is suddenly leaked out into the air, unexpected ignition occurs without any external ignition source. Until now, there have been investigations on self-ignition of hydrogen by supplying high-pressure hydrogen gas into a tube. However the mechanism of hydrogen ignition is still unclear. This paper describes the area-ratio effect on hydrogen ignition by inserting a brass plate. The results show that the ignition phenomena differ as the area-ratio changed. Also, the rupture pressure for self-ignition has to be higher.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.247-248
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• 2012

Unidentified self-ignitions were reported when the high-pressure hydrogen gas suddenly leaked out. This paper presents a flow visualization study to investigate the self-ignition mechanism in a test tube how the ignition process is initiated and the flame propagates with measurement of a number of pressure and light sensors installed in the tube supported the analysis of the self-ignition. The test result showed the location of the self-ignition taken place and critical static pressure at the boundary layer for self-ignition.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.215-218
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• 2014

High combustion efficiency of hydrogen could make it an ideal source of green energy in the future. At this time, high pressure vessel is the most reasonable method of storing hydrogen. However, such a high pressurized vessel could pose a critical threat if ruptured. For this reason, it is important to understand the mechanism of hydrogen's self-ignition when a high-pressure hydrogen released into air. This paper presents several visualization images as experimental results using high-speed camera. From the visualization images, the ignition is initiated near rupture disk immediately after failure of disk. And the initial ignition and flame is stronger as a rupture pressure increases. However, this ignition region do not affect the general self-ignition mechanism when a high-pressure hydrogen is released into air through tue after failure of disk.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.245-246
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• 2012

The possibility that self-ignition can be generated near an obstacle is high in practical applications such as a hydrogen car. In this paper, experimental investigations were suggested to understand the effects of a wall on self-ignition phenomena through high-speed images. The results showed that the existence of a wall could not change the ignition phenomena itself irrespective of wall height and burst pressure. However, when a strong flame was induced in the tube, a wall could promote the flame stabilization.

• Fire Science and Engineering
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• v.17 no.4
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• pp.117-123
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• 2003

In this study; the ignition and heat release rate characteristics of rigid polyurethane foam were investigated in accordance with setchkin ignition tester and cone calorimeter which is using oxygen consumption principle. In the ignition temperature study; flash-ignition temperature was $383^{\circ}C$-$390^{\circ}C$, self-ignition temperature was$ 493^{\circ}C$∼495$^{\circ}C$. The self-ignition temperature of rigid polyurethane foam was about $100^{\circ}C$ higher than the flash-ignition temperature. In the cone calorimeter study, the time to ignition of rigid polyurethane foam was faster as the external heat flux increase. In the same heat flux level, the time to ignition was faster as the density of rigid polyurethane foam decrease. Also the heat release rate was the largest value at the heat flux of /$50 ㎾\m^2$ and had a tendency of increase as the heat flux level and density increase. In the standpoint of time to ignition and heat release rate, the fire performance of rigid polyurethane foam was influenced by the applied heat flux level and density and the flashover propensity classified by Petrella's proposal was high.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.1
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• pp.56-62
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• 2005

In this study, A controlled auto-ignition (CAI) single cylinder gasoline engine is considered, focusing on the extension of operating conditions. The fuel is injected indirectly into electrically heated inlet air flow. Investigated are the engine performance characteristics under the wide range of operating conditions such as 32 to 63 in the air-fuel ratio, 1000 to 1800 rpm in the engine speed, and 150 to $180^{\circ}C$ in the inlet-air temperature. A controlled auto-ignition gasoline engine which has the super ultra lean-burn with self-ignition of gasoline fuel can be achieved by heating inlet air.

• Journal of the Korean Society of Safety
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• v.22 no.1 s.79
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• pp.36-39
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• 2007

It is important to know Minimum Ignition Energy(MIE) of flammable materials for ignition hazard of chemical processes etc.. Currently a capacitor discharge is used mainly to measure the MIE. Then, it is impossible to control actively discharge energies and discharge time because the MIE measurement uses a high voltage capacitor and fixed capacitor. However, the control of discharge energy and discharge time will be convenient if self-sustain discharge is used. In this paper, we measured the MIE by self-sustain discharge of a pulse shape to propose the new measuring method of the MIE. AS a result, ignition energies are increased gradually as discharge duration time gets longer, and discharge current grows larger. Also, an arc discharge and a glow discharge occurred during the experimental period, and the ignition by glow discharges happened when discharge duration time was $90{\mu}s$, discharge current was 8A and 1A Especially, the MIE occurred the 0.05mm and 0.08mm of the gap distance between discharge electrode in the same discharge duration time.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.11-12
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• 2013

To investigate the effect of an inner diameter of the extension tube on the self-ignition when high pressurized hydrogen abruptly released through a tube, both experimental and numerical approach are used. The result show that there is a possibility to have successful ignition when the tube diameter is decreased even at the pressure that could not give sustainable flame with a larger diameter tube. Numerical simulation show the flame development inside the tube and weak and stretch flame spout the tube for 10.9 mm tube, whereas strong complete flame has been generated for 3 mm tube.

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.48-52
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• 2001

This study was undertaken to investigate fire risk characteristics of the plastics foam that is used an insulating materials in workplaces. The ignition characteristics and combustion gas of the plastics foam were carried out using the ISO self-Ignition tester, the Cone Calorimeter, and NES combustion analyzer. The experimental materials used were commercial samples and their composition is not disclosed by the manufacturer. As the experimental results, the self-ignition temperature of the plastics foam ranges from $410^{\circ}C$ to $510^{\circ}C$, and the flash-ignition temperature of plastics foam ranges from $370^{\circ}C$ to $450^{\circ}C$. The difference of ignition temperature on density with plastics foam type was smaller since the amount of combustible gas to ignite is not caused enough. The time to ignition of the polyethylene foam in samples of the plastics foam was shorter, and its of polyethylene foam was longer. The concentration of carbon dioxide of the polyethylene foam shows higher in samples of the plastics foam. It is found that the concentration values of carbon monoxide of the plastics foam show very fatality on people during exposure of 30 minutes in fire.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.7
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• pp.1007-1014
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• 2003

This work deals with a controlled auto-ignition (CAI) single cylinder gasoline engine, focusing on the extension of operating conditions. The fuel is injected indirectly into electrically heated inlet air flow. In order to keep a homogeneous air-fuel mixing, the fuel injector is water-cooled by a specially designed coolant passage. Investigated are the engine performance and emission characteristics under the wide range of operating conditions such as 32 to 63 in the air-fuel ratio, 1000 to 1800 rpm in the engine speed, and 150 to 18$0^{\circ}C$ in the inlet air temperature. The compression ignition gasoline engine can be achieved that the ultra lean-burn with self-ignition of gasoline fuel by heating inlet air. For example. the allowable lean limit of air-fuel ratio is extended until 63 at engine speed of 1000 rpm and inlet air temperature of 17$0^{\circ}C$. It can be achieved that the emission concentrations of carbon monoxide, hydrocarbons and nitrogen oxide had been significantly reduced by CAI combustion compared with conventional spark ignition engine.