• 한국추진공학회:학술대회논문집
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• 한국추진공학회 1995년도 제5회 학술강연회논문집
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• pp.139-144
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• 1995

The main purpose of igniter is sure ignition of main propellant at desired ignition delay times. Since ignition mechanism of solid rocket propellant involves so many complicated physical and chemical phenomena, it is almost impossible to predict ignition behavior with pure analytical means. In this study, one dimensional and unsteady ignition transient phenomena in solid rocket was analyzed by finite volume method. In analysis, assumption was made that ignition occurs when propellant surface temperature reaches to it's auto-ignition temperature.

• 한국화재소방학회논문지
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• 제15권4호
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• pp.34-40
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• 2001

HPMC의 자연발화는 일정한 주위온도에서 자연발화의 연구와 Godbret-Greenwald가 고안한 전기로에서 운상상태의 최소발화온도를 구하였으며, 시료를 용기에 충전했을 경우 용기의 크기가 클수록 발화한계 온도는 낮아졌으며 겉보기활성화에너지는 Frank-Kamenetskii의 열발화이론으로부터 계산하였고, 운상상태의 발화온도는 21%의 산소농도하에서 최소발화온도를 구하였으며, 산소농도 변화의 실험결과 산소농도 10%에서 발화되지 않았으며 한계산소농도를 구할 수 있었다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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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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• 한국연소학회 2013년도 제46회 KOSCO SYMPOSIUM 초록집
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• pp.5-8
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• 2013

The ignition of aluminum particles under high pressure and temperature conditions is studied. The laser ablation method is used to generate aluminum particles exposed to pressures ranging between 0.35 and 2.2 GPa. A continuous wave $CO_2$ laser is then used to heat surface of the aluminum target until ignition is achieved. We confirm ignition by a spectroscopic analysis of AlO vibronic band of 484 nm wavelength. The radiant temperature is measured with respect to various pressures for tracing of required heating energy for ignition. Then the ignition temperature is deduced from the radiant temperature using the thermal diffusion equation. The established ignition criteria for corresponding temperature and pressure can be used in the modeling of detonation behavior of heavily aluminized high explosives or solid propellants.

• 한국군사과학기술학회지
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• 제14권6호
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• pp.1166-1170
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• 2011

For developing the ignition device for the interceptor of Korean active protection system, the design parameters of the ignition device which should have a short ignition delay time and sufficient energy for propellant ignition were studied. The electric primer instead of mechanical primer was adopted for deceasing delay time, and ignition code was used for decreasing the time difference of flame propagation from the flame holes. The developed ignition device showed the ignition delay time of a few ms. When the designed ignition device was applied to the open-type propulsion devices, the stable interior ballistic characteristic was showed in a firing test.

• 한국주조공학회지
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• 제31권2호
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• pp.60-65
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• 2011

Molten magnesium alloys and magnesium products are easily oxidized and burned when they are exposed to high temperature for manufacturing process and by accident. In order to solve these problems, CaO addition in magnesium alloys has been developed. The ignition resistance of CaO added Mg-3Al, Mg-6Al, and Mg-9Al Eco-Mg alloys were investigated in comparison with those of magnesium alloys without CaO. The ignition resistance was examined by three methods : DTA, furnace chip ignition test, and torch ignition test. DTA was carried out for obtaining quantitative ignition temperature data with respect to specimen geometry and test environment; the furnace ignition test for burr and chip ignition temperature data; and the torch test for ignition temperature data for manufactured products. The ignition resistance of magnesium alloys under all conditions greatly increased by CaO addition.

• 한국연소학회지
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• 제18권4호
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• pp.12-20
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• 2013

The ignition delay time is an important factor to understand the combustion characteristics of internal combustion engine. In this study, ignition delay times of cool and thermal flame were observed separately in homogeneous charge compression ignition(HCCI) engine. This study presents numerical investigation of ignition delay time of n-heptane and alcohol(ethanol and n-butanol) binary fuel. The $O_2$ concentration in the mixture was set 9-10% to simulate high exhaust gas recirculation(EGR) rate condition. The numerical study on the ignition delay time was performed using CHEMKIN codes with various blending ratios and EGR rates. The results revealed that the ignition delay time increased with increasing the alcohol fraction in the mixture due to a decrease of oxidation of n-heptane at the low temperature. From the numerical analysis, ethanol needed more radical and higher temperature than n-butanol for oxidation. In addition, thermal ignition delay time is sharply increasing with decreasing $O_2$ fraction, but cool flame ignition delay time changes negligibly for both binary fuels. Also, in high temperature regime, the ignition delay time showed similar tendency with both blends regardless of blending ratio and EGR rate.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.814-819
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• 2017

본 논문에서는 점화 위치 및 시간에 따른 점화 지연 및 연소 불안정에 미치는 영향을 관찰하는 것이 목표이다. 산화제는 기체 산소를 사용하였고 연료는 액체 케로신을 사용하였다. 점화 지연 및 연소 불안정 정도를 관찰하기 위해 압력 트랜스듀서를 이용하여 정압을 측정하였다. 점화 위치는 분사기 스페이서를 이용하여 변경하였다. 모든 경우의 점화기 작동 시기를 제외한 점화 시퀀스는 동일하게 설정하였고 점화 시간은 25 ms 간격으로 설정하였다. 점화 시간이 늦어질수록 초기 압력 피크값과 점화 지연 시간이 증가하는 경향을 보였다. 점화 위치가 분사기로부터 멀어질수록 초기 압력 피크 이후 불안정한 화염 발달 구간이 존재하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 1995년도 제5회 학술강연회논문집
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• pp.11-30
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• 1995

The ignition characteristics of a reactive solid with rough surface by constant heat flux were studied. The geometry of surface was represented by a set of identical protrusions having a shape of wedge based on the block of reactive solid. Several regimes of ignition were found, depending on the ratio of the protrusion length and the depth of the heated layer, formed in course of ignition process: 1) when the substance is ignited as the massive block, and the effect of roughness is not pronounced; 2) when ignited are the individual protrusions; and 3) in the intermediate region between the first two. Critical ignition conditions: ignition time and ignition criterion, are determined for the three regimes. The results are compared with the results for the one-dimensional ignition of the semi-infinite body. It is shown, that the effect of geometry on ignition results in the considerable reduction of ignition delay, and the amount of energy required for the successful ignition is less compared to the one- dimensional case.

• 한국안전학회지
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• 제36권3호
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• pp.1-6
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• 2021

Hydrogen is considered a cleaner energy source than fossil fuels. As a result, the use of hydrogen in daily life and economic industries is expected to increase. However, the use of hydrogen energy is currently limited because of safety issues. The rate of combustion of the hydrogen mixture is about seven times higher than that of hydrocarbon fuels. The hydrogen mixture is highly flammable and has a low minimum ignition energy. Therefore, it presents considerable risks for fire and explosions in all areas of hydrogen manufacturing, transportation, storage, and use. In this study, the auto-ignition characteristics of hydrogen were investigated numerically for diluted hydrogen mixtures. Auto-ignition temperature, a critical property predicting the fire and explosion risk in hydrogen combustion, was determined in well-stirred reactors. When N₂ and CO₂ were used to dilute the hydrogen/air mixture, the ignition delay time increased with increasing dilution ratios in both cases. The CO₂-diluted mixtures exhibited a longer ignition delay than the N₂-diluted mixtures. We also confirmed that lower initial ignition temperatures increased the ignition delay times at 950 K and above. Overall, the auto-ignition characteristics, such as the concentrations of participating species and ignition delay times, were primarily affected by the initial temperature of the mixture.