• KEPCO Journal on Electric Power and Energy
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• 제2권1호
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• pp.89-96
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• 2016

The mechanism for laminar dust flame propagation can only be elucidated from a comprehensive mathematical model which incorporates conduction and radiation, as well as the chemical kinetics of particle devolatilization and gas phase and char reaction. The mathematical model for a flat, laminar, premixed coal-air flame is applied to the atmospheric coal-air mixtures studied by Smoot and co-workers, and comparisons are made with their measurements and predictions. Here the principal parameter for comparison is the laminar burning velocity. The studies of Smoot and co-workers are first reviewed and compared with those predicted by the present model. The effects of inlet temperature and devolatilization rate constants on the burning velocities are studied with the present model, and compared with their measurements and predictions. Their measured burning velocities are approximately predicted with the present model at relatively high coal concentrations, with a somewhat increased inlet temperature. From the comparisons, their model might over-estimate particle temperature and rates of devolatilization. This would enable coal-air mixtures to be burned without any form of preheat and would tend to increase their computed values of burning velocity.

• Journal of the Korean Wood Science and Technology
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• 제32권1호
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• pp.73-79
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• 2004

간벌재로 제조된 톱밥보드를 페놀수지에 함침율 40-80%로 함침시킨 후 소성온도 600-1500℃에서 소성하여 우드세라믹을 제조한 다음 수지함침율과 소성온도에 따른 우드세라믹의 밀도변화, 중량 및 치수감소율과 열전도성을 조사하였다.수지 함침율과 소성온도가 증가함에 따라 밀도는 커졌으나 소성온도 1200℃ 이후에는 밀도가 낮아졌다. 소성 후 치수 및 중량감소율은 수지함침율이 증가할수록 낮아졌으나 소성온도가 높을수록 커졌다. 열전도성은 수지함침율이 높을수록 우수하였으며, 소성온도와는 뚜렷한 경향을 발견할 수 없었다.

• 한국산업융합학회 논문집
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• 제11권1호
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• pp.5-10
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• 2008

A flame speed of methane mixture of water vapor and air have been measured to study the process of flame propagation using schlieren photographs. The quantity of water vapor contained were changed 5% and 10% of total mixture, and equivalence ratio of mixture between 0.8 and 1.2 were tested under the ambient temperature 323K and 373K. The results showed that the burning velocity was decreased by increasing the water vapor contents due to the interruption of flame development. And, the reduction rate of burning velocity was smaller by increasing the water contents under the same ambient temperature. The effects of ambient temperature on burning velocity was decreased by increasing the water vapor contents.

• 한국안전학회지
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• 제8권1호
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• pp.35-46
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• 1993

This paper was concerned with the risk assessment about oxidizing substances as dangerous goods by burning test method. The sample. which was formed with the heaped cone-shape. was composed of solid oxidant and sawdust. The burning time of each sample was measured under the following various conditions circumstance temperature. mixing ratio of oxidizing substance and sawdust. particle size of sawdust and kinds of sawdust. As a results. the effective combustibility was gained when the sawdust content was 20∼30 wt.% in the sample and the lauan with -30+50 mesh was used. But. although the circumstance temperature increased. burning efficiency of the samples wet$.$e not affect by it. Finally. the average burning times were obtained by considering the weighting factors related on the mixing ratio and the circumstance temperature. And then. it were compared with the combustion risk level and the effects of cation and anion of oxidizing substances as dangerous goods.

• 한국산업융합학회 논문집
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• 제9권1호
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• pp.21-27
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• 2006

The laminar burning velocity was measured using a spherical combustion bomb with central ignition. Mixtures with equivalence ratio between 0.6 and 1.2, were tested. The computation was carried out for the burning velocity using premix code of Chemkin program under the unburned gas pressure of 0.5bar-30bar and temperature of 300K-700K at ${\Phi}1.0$. The results showed little difference between these two methods. The burning velocity was decreased by increasing the pressure and increased by increasing the temperature. The burning velocity was predicted by using the following equations $$S_L(m/s) = S_{st}(T/300)^{1.85}(P)^{-0.45}$$ $$(0.5bar{\leq}P{\leq}30bar,\;300K{\leq}T{\leq}700K)$$).

• 한국추진공학회지
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• 제9권2호
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• pp.1-8
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• 2005

가스발생기용 저 연소속도 HTPB/AP계 고체추진제의 조성에서 냉각제인 Oxamide와 Melamine이 추진제의 연소특성에 미치는 효과를 고찰하였다. 냉각제의 함량을 증가시키면 연소속도와 화염온도가 낮아지고, 두 냉각제의 화염온도에 미치는 영향은 유사하였다. 그러나 냉각제의 열분해 특성 차이로 인하여 Melamine 추진제에서는 비정상적으로 $200{\mu}m$ AP의 일부를 $6{\mu}m$ AP로 대체하면 연소속도가 오히려 감소하는 현상을 나타내었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.311-316
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• 2010

The ignition and the burning characteristics of aluminum and magnesium particles ($30-110{\mu}m$ in diameter) isolated due to electrodynamic levitation were experimentally investigated. The burning time, the ignition delay time, the flame temperature, and the flame diameter were measured. The thermal radiation intensity was measured using the photomultiplier tube and the combustion history was monitored by high-speed cinematography. Two-wavelength pyrometry measured the temperature of the burning particles. The burning times of aluminum particles were measured approximately 5 to 8 times longer than those of magnesium particles. Exponents of $D^n$-law, for the burning rate of magnesium and aluminum particles of diameters less than $110{\mu}m$, are found to be 0.6 and 1.5, respectively. The instant of aluminum ignition is clearly distinguished with the ignition delay time little less than 10 ms, however the burning history of magnesium particle exhibits no distinct instant of the ignition. The ignition delay time of magnesium particle (less than $110{\mu}m$) were approximately shown in the range from 50 to 200 ns. The flame temperatures of single metal particles are lower than the boiling point of the oxide. The nondimensional flame diameters for magnesium are decreased with increasing of the diameter. The nondimensional flame diameters for aluminum are not changed significantly.

• 한국안전학회지
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• 제18권1호
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• pp.71-75
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• 2003

The purpose of this study was to review the factors that influence on the combustion experiment of oxidizing solid such as mixing ratio of oxidizing solid and combustible support content ratio of oxidizing solid, ambient temperature, maturing time, combustible support, and additives. The 30g mixing compound samples of oxidizing solid and combustible support were tested with different mixing ratios. As a result, the Infest burning time was measured when mixing ratio was 4 (oxidizing solid) : 1 (combustible support). And the burning time was decreasing as the ambient temperature and maturing time were increasing.

• 임산에너지
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• 제21권1호
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• pp.1-6
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• 2002

본 연구는 MDF로 제조된 우드세라믹을 이용하여 온돌마루판 시공 시 하부소재로서의 사용가능성을 검토하고자 실시하였다. 650℃와 800℃로 소성하여 제조된 우드세라믹을 발열판 위에 올려놓고 발열판의 온도 및 시간의 경과에 따른 우드세라믹의 표면온도의 변화를 측정하였다. 우드세라믹의 표면온도는 밀도가 증가함에 따라 표면온도가 증가하였으며, 바닥온도의 변화에 따른 표면온도는 바닥온도가 증가함에 따라 표면온도가 증가하여, 측정온도가 높을수록 열전도가 빠름을 알 수 있었다. 그러나 우드세라믹 제조 시 소성온도에 따른 표면온도의 변화는 뚜렷한 차이를 발견할 수 없었다.

• 한국연소학회지
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• 제7권2호
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• pp.1-6
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• 2002

Characteristics of laminar lifted flames of propane highly-diluted with nitrogen have been investigated at various temperatures of coflow air. At various fuel mole fractions, the base of laminar lifted flames has the structure of tribrachial (or triple) flame. The liftoff heights are correlated well with the stoichiometric laminar burning velocity considering initial temperature at a given coflow velocity. It shows that lifted flames are stabilized on the basis of the balance mechanism between local flow velocity and the propagation speed of tribrachial flame, regardless of the temperature of coflow and fuel mole fraction. Lifted flames exist for a jet velocity even smaller than the stoichiometric laminar burning velocity, and liftoff velocity increases more rapidly than stoichiometric laminar burning velocity as coflow temperature increases. These can be attributed to the buoyancy effect due to the density difference.