• 한국연소학회:학술대회논문집
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• 1998.10a
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• pp.103-110
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• 1998

This experiment is performed to investigate the effects of the emulsion on the flame temperature and soot formation in a diesel engine. The two-color method is used to measure the flame temperature for combustion of emulsified diesel in the Rapid Compression and Expansion Machine(RCEM). The concentration of soot is estimated via calculation of the KL factor. The solenoid valve, elecronic controller and needle lift sensor are used to control the exact injection timing and duration under various operating conditions. According to the results the soot concentration is reduced with the increasing W/O while the temperature reduced. The pressure data and the flame images captured by a high speed camera show that the ignition delay of emulsified diesel increase the duration of premixed combustion. The sizes of water drops are measured to be about 10${\mu}m$ by a microscope.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.254-255
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• 2005

The effect of surrounding air velocity on the soot deposition process from a diffusion flame to a solid wall was investigated in a microgravity environment to attain in-situ observations of the process. An ethylene($C_2H_4$) diffusion flame was formed around a cylindrical rod burner in surrounding air velocity of $v_{air}$=2.5, 5, and 10 cm/s with oxygen concentration of 35 % and wall temperature of 300 K. Laser extinction was adopted to determine the soot volume fraction distribution between the flame and burner wall. The experimental results show that the soot particle distribution region moves closer to the surface of the wall with increasing surrounding air velocity. A numerical simulation was also performed to understand the motion of soot particles in the flame and the characteristics of the soot deposition to the wall. The results successfully predicted the differences in the motion of soot particles by different surrounding air velocity near the burner surface and are in good agreement with observed soot behavior in microgravity. A comparison of the calculations and experimental results led to the conclusion that a consideration of the thermophoretic effect is essential to understand the soot deposition on walls.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.9
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• pp.1117-1123
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• 2004

The characteristics of soot near the soot inception point for an ethene-air flame was carried out in a WSR (well-stirred reactor). The new sampling tool like the temperature controlled filter system was introduced to minimize the condensation during sampling. The new analysis tools applied include the real time size distribution analysis with the Nano-DMA, particle size by transmission electron microscopy, C/H analysis, g filter analysis, and thermogravimetric analysis using both non-oxidative and oxidative pyrolysis. The WSR can generate young soot particles that can be collected and examined to gain insight into inception. For the current conditions, soot does not form for ${\Phi}$=1.9, inception occurs at or before ${\Phi}$=2.0, and inception combined with soot surface growth and/or coagulation occurs for ${\Phi}$=2.1. The filter samples for ${\Phi}$=1.9 are composed of volatile compounds that evolve at relatively low temperatures when heated in the presence or absence of O$_2$. The samples collected from the WSR at ${\Phi}$=2.0 and ${\Phi}$=2.1 are precursor-like in morphology and size. They have higher C/H ratios and lower organic percentages than precursor particles, but they are clearly not fully carbonized soot. The WSR PAH distribution is similar to that in young soot from inverse flames.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1298-1303
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• 2004

The characteristics of soot near the soot inception point for an ethene-air flame was carried out in a WSR (well-stirred reactor). The new sampling tool like the temperature controlled filter system was introduced to minimize the condensation during sampling. The new analysis tools applied include the real time size distribution analysis with the Nano-DMA, particle size by transmission electron microscopy, C/H analysis, g filter analysis, and thermogravimetric analysis using both non-oxidative and oxidative pyrolysis. The WSR can generate young soot particles that can be collected and examined to gain insight into inception. For the current conditions, soot does not form for ${\Phi}=1.9$, inception occurs at or before ${\Phi}=2.0$, and inception combined with soot surface growth and/or coagulation occurs for ${\Phi=2.1}$. The filter samples for ${\Phi}$=1.9 are composed of volatile compounds that evolve at relatively low temperatures when heated in the presence or absence of $O_2$. The samples collected from the WSR at ${\Phi}=2.0$ and ${\Phi}=2.1$ are precursor-like in morphology and size. They have higher C/H ratios and lower organic percentages than precursor particles, but they are clearly not fully carbonized soot. The WSR PAH distribution is similar to that in young soot from inverse flames.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.137-142
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• 2003

In order to investigate the effect of fuel mixing on PAH and soot formation, four species of methane, ethane, propane and propene have been mixed in counterlfow ethylene diffusion flame. Laser-induced incandescene and laser-induced fluorescene techniques were employed to measure soot volume fraction and polycyclic aromatic hydrocarbon (PAH) concentration, respectively. Results showed that the mixing of ethane (or propane) in ethylene diffusion flame produces more PAHs and soot than those of propene, even though the propene diffusion flame produces more PAHs and soot than that of propane and ethane. Considering that propene directly dehydrogenates to propargyl radical, this behavior implied that the enhancement of PAH and soot formation by the fuel mixing of ethylene and ethane (or propane) cannot be explained by propargyl radical directly dehydrogenated from ethane (or propane).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.11
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• pp.1355-1362
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• 1999

An experimental study on a double-concentric diffusion flame(DDF) has been carried on in order to Investigate the characteristics of soot formation compared to a normal coflow diffusion flame(NDF). Laser extinction technique has been used for an ethylene($C_2H_4$) and air flame with various flow rates. Soot formation In the double-concentric diffusion flame was enhanced by the inner inverse diffusion flame due to the increase in flame temperature and also suppressed due to the nitrogen-dilution from the inner air. Soot concentration at the flame axis of DDF was higher than that of the NDF, mainly because of the increase of temperature by inner flame. However, the maximum soot volume fraction of DDF was lower than NDF at the outer side of the flame, mainly due to the effect of nitrogen-dilution from the inner air.

• Tribology and Lubricants
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• v.19 no.5
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• pp.251-258
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• 2003

New method and device for the on-line measurement of soot concentration in a diesel engine oil are proposed, where the measurement principle is based mainly on attenuated internal total reflection. The detector were evaluated in various ranges of contaminated oils by carbon black particles. It was found that the proposed detector could be well used to monitor the oil deterioration due to soot contamination. Operational range of the detector was found from 0 to 5 mass percentage of soot content. Test results with water and fuel dilution showed that these effects were not remarkable. However, adsorption of carbon black particles onto the measurement surface was considered to be a critical problem of the detector. Effects of particle deposition on the interface was experimentally evaluated with the oil temperature and flow turbulence and discussed throughout this work.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.9
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• pp.3007-3014
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• 1996

The instantaneous flame temperature and soot formation and oxidation in a D.I. diesel engine are measured using a two-color method. The proposed method based on the continuous spectral radiation from the soot particles in the flame is applicable to industrial diesel engines without major modifications of their main characteristics. Measurements are performed at one location inside the combustion chamber of a D.I. diesel engine. Effects of different engine speeds and loads on flame temperature and KL factor which is an index of soot concentration were examined. Little temperature change were observed with increasing rpm, while increased with loads. The higher the flame temperature is, the lower the KL factor is.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.162-167
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• 2000

Soot formation and oxidation is closely related to the combustion phenomena inside a diesel engine. Laser-based diagnostics provide a means for improving our understanding of diesel combustion, because they have highly temporal and spatial ability. To understand the soot behavior we did preliminary study by taking flame luminosity photographs and 2-D imaging soot distribution using Laser Elastic Scattering(LIS) and Laser-Induced Incandescence(LII). From the data we found that soot concentration was high in the bowl and disappeared from the central region in the late combustion stage.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.261-264
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• 2015

Soot particles of diesel and bunker-A with different sulfur contents were generated by pyrolysis with varying conditions of fuel flow rate and residence time in the ceramic tube at $1300^{\circ}C$. TEM and particle size analyzer were used for analysing the primary and the secondary particle size distributions. The results showed that the sulfur content in fuel influences soot inception while the fuel concentration and residence time affects the growth of incepted soot particles.