• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.113-121
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• 2002

The distribution of volume fraction, mean diameter and number density of soot particles are measured quantitatively in a co-flow ethylene diffusion flame using a simultaneous LII/LIS measurement technique. The LII/LIS system and the measured values are, respectively, calibrated and evaluated by comparing to the informations obtained from laser light. extinction/scattering experiments, LII signal shows some sensitivity to the laser light intensity when laser power density exceeds a certain value(threshold). It is also found that there is an optimal laser intensity and a delay time in order to obtain the best result using the simultaneous LII/LIS measurement technique.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.641-646
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• 2016

Soot particles generated by fossil fuel combustion normally have fractal morphology with aggregates consisting of small spherical particles. Thus, Rayleigh or Mie elastic light scattering theory is not feasible for determining the fractal properties of soot aggregates. This paper describes a detailed process for applying Rayleigh-Debye Gans (RDG) scattering theory to effectively extract the morphological properties of any nano-scale particles. The fractal geometry of soot aggregates produced from an isooctane diffusion flame was observed using ex situ transmission electron microscopy (TEM) after thermophoretic sampling. RDG scattering theory was then used to analyze their fractal morphology, and various properties were calculated, such as the diameter of individual soot particles, number density, and volume fraction. The results show indiscernible changes during the soot growth process, but a distinct decreasing trend was observed in the soot oxidation process. The fractal dimension of the soot aggregates was determined to be around 1.82, which is in good agreement with that produced for other types of fuel. Thus, it can be concluded that the value of the fractal dimension is independent of the fuel type.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.42-53
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• 1999

Two dimensional flame temperature and KL value distribution from the luminous flame containing soot in a DI diesel engine were measured by the tow-color method using tow different wavelengths of the flame image. The combustion chamber of a DI diesel engine was visualized by elongating the piston and cylinder and the flame in the combustion chamber was photographed on a nega-color film using a high speed camera. In this study, color CCD camera was used to digitize the three color density of the film exposed to the flame and standard lamp . The accuracy of the measuring method depends on the calibration line of film made from a high temperature standard tungsten lamp. The formation and oxidization of soot in the diesel engine were studied by observing measured time history of KL factor and flame temperature . Also , effects of various shapes of combustion chamber and fuel injection on flame temperature. Also, effects of various shapes of combustion chamber and fuel injection on flame temperature and KL value distribution were examined.

• Fire Science and Engineering
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• v.33 no.1
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• pp.76-84
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• 2019

Experimental studies using an open cone calorimeter were conducted to provide information on the CO and soot yields of wood combustibles required for a kitchen fire simulation of PBD. A total of eight specimens were examined for medium density fiberboard (MDF) and particle board (PB), which are used widely in kitchen furniture production, depending on the water content, surface processing method, and surface color. The thermal penetration time related to the fire spread rate in the depth direction differed significantly according to the surface processing treatment method, even for a specimen of identical thickness. The CO yield ($y_{CO}$) of the MDF and PB series did not change significantly according to the combustion mode and surface treatment process in flaming mode. On the other hand, $y_{CO}$ was approximately 10 times higher in smoldering mode than in flaming mode. The soot yield ($y_{soot}$), however, varied considerably depending on the combustion mode and surface treatment process. In particular, a higher $y_{soot}$ was found in flaming mode and in the surface-treated specimens. Finally, the $y_{CO}$ and $y_{soot}$ of MDF and PB measured for the kitchen fire simulation of PBD were applied.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.4
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• pp.68-76
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• 2006

The minimization of maximum DPF wall temperature and the fast Light-off during regeneration are the targets for the high durability of the DPF system and the high efficiency of regeneration. In order to predict transient thermal response of DPF, one-channel numerical modeling has been adopted. The effect of the ratio of length to diameter(L/D), cell density, the amount of soot loading on temporal thermal response and regeneration characteristics has been numerically investigated under two different running conditions: city driving mode and high speed mode. The results indicate that the maximum wall temperature of DPF increase with increasing 'L/D' in 'High speed mode'. For 'City driving mode', the maximum wall temperature decreases with increasing 'L/D' in the range of $'L/D{\geq}0.6'$. The maximum temperature decreases with increasing cell density because heat conduction and heat capacity are increased. It is also found that the effect of amount of soot loading on light-off time is negligible.

• Journal of the Korean Society of Combustion
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• v.8 no.2
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• pp.41-49
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• 2003

Ultrasonic field of 28kHz with sound pressure level 162dB has been employed to agglomerate the fine soot particle produces in a diffusion flame in a chamber. The agglomeration process has been investigated with digital camcorder and analysed in terms of the decrease of number density with exposure time. From the observation of agglomeration process, the initial agglomeration has been carried out during the short time, and it has been dominated by the orthokinetic collision. Thereafter, a slower agglomeration mechanism, driven by acoustic streaming in the chamber takes over and agglomeraters grew to diameters of several millimeters were levitated at the pressure node of the acoustic wave. And, the circular disk shape of large agglomeraters with the rotational and translational motion is observed.

• Proceedings of the KIEE Conference
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• 1984.07a
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• pp.226-229
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• 1984

A novel high intensity charging device has been developed for the control of the submicron particles, such as the diesel soot particulates, which are very hard to charge highly by any means of the conventional charging device. Having new corona electrodes of a multineedle disk with the corona field-control electrodes in the outer-cylinder electrode, extremely intense and stable coronas on there sharp points expanding both radially and axially are established in the corona charging region between the multi-corona -needles and an outer-cylinder electrode. As a result, the maximum corona field intensity and current density of the charging device of the standard one on soot load in laboratory tests have been 8.5KV/cm(E=$2V_m$/D(1nD/d)) and $6.5{\mu}A/cm^2$ which enhance greatly the charging of soot particles about several 100 times higher than those obtained in conventional cylinder precipitators.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.50-51
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• 2009

This paper aims to improve survival ratio at ship fires by soot density reduction This study examines soot density and visibility using FDS. And also examines evacuation time by Pathfinder. The FDS(Fire Dynamic Simulator) is a 3 zone model(Field Model) analysis tool and the patherfinder is a useful analysis tool for evacuation. This research examined about evacuation time using the current regulations of the ship's corridor width and exit width first And then studied evacuation time again when ship's structure was changed according to the method that is proposed in this paper. And finally compared the results each other.

• Journal of the Korean Society of Safety
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• v.23 no.6
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• pp.38-43
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• 2008

Significant portion of the fire accident is caused by some troubles in electric circuits. To prevent the fire induced by those electric trouble, some indications of electric fire need to be suitably detected at the first stage of the fire development. With this background, the characteristics of soot yielding of electric cables have been investigated using a light extinction method. In this study, a light scattering method was compared with the light extinction method. A slot-type premixed-flame combustor was traversed to bum three types of electric cables by compulsion, then the mass decrease rate and the soot densities were measured. According to the experimental results, the light scattering method is preferred to the light extinction method when the soot yield ratio is relatively small. Thus the former method is more suitable to detect the occurrence of an electric fire in a power distributer box.

• Korean Journal of Materials Research
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• v.5 no.6
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• pp.732-742
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• 1995

Effects of the substrate pretreatment on uncleation density of the diamond thin films have been investigated. The film was prepared using the hot-filament CVD reactor with the mixture of methane and hydrogen. The substrate pretreatment was done in three different ways: predeposition of carbon on the substrate, soot on the substrate, and graphite on the substrate. All three cases enhanced the nucleation density of diamond. And the effect was more marked in the first and the second cases than in the third one. In the first case where the substrate was predeposited by the carbon phase, a very smooth and uniform film of diamond could be obtained. Since the bound strength between the substrate and the predeposited carbon phase is relatively weak, separation of the diamond film layer from the substrate was found to be easy.