• Journal of Advanced Marine Engineering and Technology
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• 제33권3호
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• pp.378-386
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• 2009

The effect of fuel mixing on soot structure with methane, ethane, and propane to ethylene-base counterflow diffusion flames has been investigated by measuring the volume fraction, number density, and particle size of soot by adopting the light extinction/scattering techniques. The experimental result showed that the mixing of ethane and propane in ethylene diffusion flame increased soot volume fraction while the mixing of methane decreased. As compare to the ethylene-base flame, the diameters of soot particles for mixture flames are slightly smaller. While the soot number densities for the mixture flames are much higher. Thus, the increase in the soot volume fraction can be attributed to the appreciably increased soot number density by the fuel mixing.

• 대한기계학회논문집B
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• 제28권9호
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• pp.1101-1109
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• 2004

Experimental measurements of flame structure and soot characteristics were performed fur ethene inverse diffusion flames (IDF). IDF has been considered as the excellent flow field to study the incipient soot because soot particle do not experience the oxidation process. In this study, LIF image clarified the reaction zone of IDF with OH signal and PAH distribution. laser light scattering technique also identified the being of soot particle. To address the degree of soot maturing, C/H ratio and morphology of soot sample were investigated. From these measurements, the effect of flow residence time and temperature on soot inception could be suggested, and more details on soot characteristic in the IDF was determined according to fuel dilution and flame condition. The fuel dilution results in a decrease of temperature and enhancement of residence time, but the critical dilution mole fraction is existed for temperature not to effect on soot growth. Also, the soot inception evolved on the specific temperature and its morphology are independent of the fuel dilution ratio of fuel.

• Journal of Mechanical Science and Technology
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• 제15권9호
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• pp.1311-1318
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• 2001

It is necessary to diagnose accurately the characteristics of soot formation and oxidation in a diesel engine. Whereas past measurement techniques for soot concentration give limited information for soot, laser-based two-dimensional imaging diagnostics have a potential to provide temporally and spatially superior resolved measurements of the soot distribution. The technique using laser sheet beam has been applied to an optically accessible diesel engine for the quantitative measurement of soot. The results provided the information for reduction of soot from the diesel engine. Both LIS (Laser Induced Scattering) and LII (Laser Induced Incandescence) techniques were used simultaneously in this study. The images of LIS and LII showed the quantitative distribution of the soot concentration in the diesel engine. In this study, several results were obtained by the simultaneous measurements of LIS and LII technique. The diameter and number density of soot in combustion chamber of the test engine were obtained from ATDC 20 degree to 110 degree. The soot diameter increased about 37% between ATDC 20 degree and 110 degree. The number density of soot, however, decreased significantly between ATDC 40 degree and 70 degree.

• 한국자동차공학회논문집
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• 제15권5호
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• pp.78-85
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• 2007

Recently, diesel vehicles have been increased and their emission standards have been getting strict. The emission of diesel vehicles contains numerous dangerous compounds, especially particulate matters cause a serious environmental pollutant and affect to human health seriously. Thousands of studies have already reported that particulate matters are associated with respiratory and cardiovascular diseases, and death. Due to these, it is necessary to measure the soot concentration and soot particle size in laboratory flames or practical engines to recognize the soot formation, and develop the control strategies for soot emission. In this study, the characteristics of exhausted soot particle size and volume fraction from 2.0L CRDI diesel engine have been investigated as varying engine speed and load. Laser induced incandescence has been used to measure soot concentration. Time-resolved laser induced incandescence has been used to determine soot particle size in the engine. The soot volume fraction is increased as increasing engine load but soot volume fraction is decreased as increasing engine speed. The primary particle size is distributed about $35nm{\sim}60nm$ at each experimental conditions.

• 한국연소학회지
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• 제15권3호
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• pp.74-81
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• 2010

In this study, soot formation characteristics on the instability of laminar diffusion flames were investigated experimentally using a concentric co-flow burner. When a small amount of air was supplied through an inner nozzle, a stable propane laminar diffusion flame became unstable and began to oscillate mainly due to the dilution effect. The increase of air flow rate transformed an oscillating non-sooting flame into a stable nonsooting flame. When the air flow rate was continuously increased an inner flame was formed and the flame was changed to an oscillating sooting flame, an oscillating non-sooting flame and finally a stable non-sooting hollow flame. When the air flow rate was decreased, a non-sooting hollow flame was eventually changed back to a stable non-sooting flame. The presence of an inner flame, however, altered the soot formation characteristics of a flame. More soot production was observed with the presence of an inner flame. The increased or decreased soot formation/oxidation rates, the radiation heat loss, and the heating effect of inner flames are most likely to be responsible for the observed instability of laminar diffusion flames.

• 한국가시화정보학회지
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• 제2권1호
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• pp.12-17
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• 2004

The physical characteristics of soot near the soot inception point were investigated with various measurements. In-situ measurements of particle size and volume fraction were introduced based on time resolved laser-induced incandescence (TIRE-LII) and laser-induced ion mobility (LIIM). The one has more convenience and accuracy than conventional LII technique and the other works best for particle sizes of a few nanometers at high concentrations in a uniform concentration field. A complementary ex-situ measurement of particle size is nano differential mobility analyzer (Nano-DMA), which recently developed for measuring particle sizes between 2nm and 100nm and provides high-resolution size information for early soot. Particles will be also collected on transmission electron microscope (TEM) grids using rapid thermophoretic sampling and analyzed for morphology. These measurements will allow fresh and original insight into the characterizing soot inception process. The measured physical properties of incipient soot will clarify the controlling growth mechanism combined with chemical ones, and the dominant mechanism for soot modeling can be deduced from the information.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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• pp.179-184
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• 2001

The characteristics of $NO-NO_2$ conversion and soot oxidation by corona discharge are investigated experimentally. The discharge current decreases with the increase of oxygen concentration and it increases more sharply for anode corona than for cathode corona as discharge voltage increases after corona onset voltage. $NO-NO_2$ conversion increases with the energy density of corona discharge and the addition of $O_2$ in a base $N_2$ gas. Soot oxidation occurs at approximately $480^{\circ}C$ in a mixture of 21% $O_2$, base $N_2$ gas, and enhances as temperature increases. The initiation temperature of soot oxidation advances greatly to about $280^{\circ}C$ with the addition of 300ppm $NO_2$, which is generated from the conversion of NO to $NO_2$ by corona discharge. CO is generated at higher temperature by about $50{\sim}100^{\circ}C$ than $CO_2$ in the process of soot oxidation.

• Journal of Advanced Marine Engineering and Technology
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• 제32권1호
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• pp.57-65
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• 2008

The characteristics of soot deposition on the cold wall in laminar diffusion flames have been numerically analyzed with a two-dimension with the FDS (Fire Dynamics Simulator). In particular, the effects of surrounding air temperature and wall temperature have been discussed. The fuel for the flame is an ethylene ($C_2H_4$). The surrounding oxygen concentration is 35%. Surrounding air temperatures are 300K, 600K, 900K and 1200K. Wall temperatures are 300K, 600K and 1200K. The soot deposition length defined as the relative approach distance to the wall per a given axial distance is newly introduced as a parameter to evaluate the soot deposition tendency on the wall. The result shows that soot deposition length is increased with increasing the surrounding air temperatures and with decreasing the wall temperature. And the numerical results led to the conclusion that it is essential to consider the thermophoretic effect for understanding the soot deposition on the cold wall properly.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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• pp.27-34
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• 2001

The soot formation characteristics have been studied experimentally in concentric co-flow ethylene/propane diffusion flames. Comparing to the homogeneously mixed propane/ethylene case, the increase of soot formation is observed when propane is supplied through the outer nozzle, while the decrease is observed when propane is supplied through the inner nozzle. The reaction path of PAHs formed from the pyrolysis process of propane is likely to be responsible to the observed difference. When propane is supplied through the outer nozzle, PAHs formed during the combustion process are easy to be exposed to the oxidization environment; however, when propane is supplied through the inner nozzle, PAHs are not likely to be oxidized and thus get involved in soot formation process. The synergistic effect in ethylene/propane diffusion flames is affected not only by the composition of mixture but also by the way of mixing.

• 에너지공학
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• 제23권3호
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• pp.181-185
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• 2014

본 논문은 카놀라 바이오디젤 혼합연료를 승용디젤엔진에 적용하였을 때 나타나는 연소 및 배기배출물 특성에 관한 연구이다. 본 연구에서는 카놀라 바이오디젤을 20%, 40%를 ULSD 80%, 60%와 체적비로 혼합한 혼합연료를 사용하여 ULSD 결과 데이터와 비교하였다. 엔진 회전속도, 엔진부하, 연료분사압력 변화를 실험변수로 사용하였으며. 카놀라 바이오 디젤의 혼합비가 증가 할수록 NOx 배출량은 증가하였지만, Soot 배출량은 감소하는 결과를 나타내었다. 또한 Soot 배출량은 낮은 연료분사압력에서 높은 배출량을 보였다.