• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.141-143
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• 2012

The present study is aiming at numerically analyze the soot formation processes coupled with gas reaction mechanism in turbulent non-premixed and partially premixed flames. In order to realistically represent turbulence-chemistry interactions with detailed chemical kinetics and soot formation behaviour related to the turbulent non-premixed and partially premixed flames, the transient flamelet[1] and flamelet based level-set approach[2] are coupled with soot formation based on the two equation model [3] and DQMOM (Direct Quadrature Method of Moment)[4].

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.11-18
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• 2003

The soot formation and oxidation characteristics with different radiation boundary conditions have been studied experimentally in a co-flow ethylene/air laminar diffusion flame. The boundary conditions are two cases, one is a fully refractive radiation boundary condition by a polished aluminum cylinder(AL) and the other is a fully absorbing radiation boundary condition by a black body cylinder(BB). The AL case compared with BB condition show the lower inception point, denser soot volume fraction, wider and longer annular soot area owing to the reabsorption of radiating energy.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.5
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• pp.109-113
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• 2005

NOx, Soot and other exhausted components already became a dangerous state as principal materials of the air pollution. Therefore, the exhausted regulations are getting strict in the many countries. In this paper, reduction characteristic of NOx Soot and CO from diesel engine are investigated when MF plasma system is put to the diesel engine. NOx is decreased in all measured load and applied voltage to plasma reactor.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.179-186
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• 2021

In this study, we attempted to comparatively analyze the structural characteristics of soot generated from marine engines to review the possibility of recycling crankcase soot by classifying it as exhaust soot and crankcase soot. The annealing procedure was performed in an argon gas atmosphere at 2,000℃ and 2,700℃, and Raman spectroscopy and High-Resolution Transmission Electron Microscopy(HRTEM) were used to analyze the structural properties of the samples. Furthermore, digital image processing techniques were utilized to quantitatively analyze the acquired HRTEM images. The Raman analysis demonstrated a relatively high G/D ratio in the exhaust soot and annealing conditions at 2,700℃. In the HRTEM images, both soot were able to identify similar forms of graphite nanostructures, but there were limitations in that they could not quantitatively derive differences in the degree of graphite depending on the type of soot and annealing temperature. Thus, digital image processing quantitatively analyzed the length and tortuosity of the fringe of the HRTEM image, which is consistent with the Raman analysis. This meant that the exhaust soot had a more graphite structure than the crankcase soot, and that annealing at a higher temperature improved the graphite structure. This study confirmed that both the crankcase soot and exhaust soot can be recycled as a graphite materials.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1199-1206
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• 2015

In this study, the exhaust gas of a diesel engine operating on biodiesel(BD) fuel(a mixture of diesel and soybean oil) was investigated for different fuel mixing ratios in the range of BD3 to BD100. The experiments were conducted using injection pressures of 400, 600, 800, 1000, and 1200 bar. The Pearson correlation coefficient and Spearman rank-order correlation coefficient were used to quantify the NOx and Soot emissions based on the fuel mixing ratio and injection pressure. Consequently, the Pearson correlation coefficient obtained for NOx and Soot emissions according to the mixing ratio and injection pressure was -0.811 and the corresponding Spearman rank-order correlation coefficient was -0.884, which indicated that the correlation of the NOx and Soot emissions was linear. Thus, the NOx and Soot have a trade-off relationship. Moreover, at each injection pressure, the Pearson correlation coefficient was a negative number, which indicated an inversely proportional relationship between NOx and Soot.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.6
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• pp.389-395
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• 2017

This study was performed to provide the information of the soot formation behavior of octane single fuel droplet under the identical combustion conditions. To achieve this, this experimental study provide the results of the soot formation characteristics of octane droplet in accordance with different initial droplet diameter($d_0$), at the same time, experiment was conducted under the same combustion conditions which are 1.0atm of ambient pressure($P_{amb}$), 21% of oxygen concentration($O_2$) and 79% of nitrogen concentration($N_2$). Visualization of octane droplet combustion was performed by visualization system with high speed camera. The results of maximum soot volume fraction($f_{vmax}$) was almost the same under the equivalent ambient conditions regardless of initial droplet diameter. Furthermore, maximum soot volume fraction was showed the higher value in the measuring direction between $135^{\circ}$ and $315^{\circ}$ since the soot-tail is generated during two opposing igniters movement process.

• Fire Science and Engineering
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• v.26 no.5
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• pp.35-40
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• 2012

Numerical investigation was performed to study on the soot formation characteristics in the WSR according to the CO addition. Ethylene and pure air were used as a fuel and an oxidizer, respectively, and three different equivalence ratios (2.0, 2.5, 3.0) were used in the calculation. The resulted CO mole fraction of 10 % CO addition showed the maximum value in spite of the least CO supply. This means that the conversion of CO to soot and other carbon compounds is weakened under incipient soot formation. The soot volume fraction was decreased with increasing the CO addition because the important species for soot formation such as pyrene and acetylene, were decreased with the addition of CO. When the equivalence ratio was 2.5, the soot volume fraction shows the highest value, which results from the contribution of fuel rich condition and reacting temperature. Furthermore, surface growth rate and species concentrations justified the HACA mechanism for soot formation.

• Journal of Mechanical Science and Technology
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• v.16 no.6
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• pp.851-860
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• 2002

In this study, it was attempted to obtain the fundamental data for the formation and oxidation of soot from a diesel engine. Combustion of spray injected into a cylinder is complex phenomenon having physical and chemical processes, and these processes affect each other. There are many factors in the mechanism of the formation and oxidization of soot and it is necessary to observe spray combustion microscopically. In order to observe with that view, free fuel droplet array was used as an experimental object and the droplet array was injected into an atmospheric combustion chamber with high temperature. Ambient temperature of the combustion chamber, interdroplet spacing, and droplet diameter were selected as parameters, which affect the formation and oxidation of soot. In this study, it was found that the parameters also affect ignition delay of droplet. The ambient temperature especially affected the ignition delay of droplet as well as the flame temperature after self-ignition. As the interdroplet spacing that means the local equivalence ratio in a combustion chamber was narrow, formation of soot was increased. As diameter of droplet was large, surface area of the droplet was also broad, and hence evaporation of the droplet was more active than that of a droplet with relative small diameter.

• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.123-128
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• 2002

The synergistic effect of ethylene/propane and ethylene/methane mixtures on soot formation is studied experimentally with a concentric co-flow burner. The integrated soot volume fractions, laser light scattering signal and PAH concentrations are measured for different fuel supply configurations. The synergistic effect in ethylene/propane diffusion flames is found to be affected not only by the composition of mixture but also by the way of mixing. Comparing to the homogeneously mixed ethylene/propane case, the increase of soot formation is observed when propane is supplied through the inner nozzle, while the decrease is observed when propane is supplied through the outer nozzle. However, the measured PAH concentration distributions are inconsistent with the current view of the synergistic effect of ethylene./propane mixture on soot formation. Virtually no synergistic effect is observed in ethylene-methane flames regardless of the fuel supply configuration, which suggests the important role of $C_3$ species produced during the propane pyrolysis process for the synergistic effect.

• Journal of Power System Engineering
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• v.16 no.4
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• pp.5-11
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• 2012

There were some papers for diesel engine performance tests using BDF, but few article deals with the temperature and soot concentration of Bio diesel flame. Since the flame temperature of diesel engines is so high and change rapidly, an optical method for measurement of flame temperature is known as the most effective one. The two-color method regarding the visible wavelength radiation for the soot particles in flame was applied on Bio diesel flame in order to measure flame temperature and soot concentration in a diesel engine. Photo detecting device was newly designed and employed TSL250R, photo-diode, to pick-up the light information emitted from the combustion flame. As a result, real flame temperature T, as a flame brightness temperature, through Ta1, Ta2, were obtained and finally the characteristics of KL value as a soot concentration reveal the difference of combustion information between diesel fuel, blending oil and Bio diesel fuel oil.