• Fire Science and Engineering
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• v.19 no.3 s.59
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• pp.58-63
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• 2005

Experimental measurements of flames and the product properties were performed for small kerosene pool fires. which is widely used as a fire source of laboratory scale experiments with scaling modeling. The flame length and flickering frequency were investigated for the flame structures, and compared with the theory. Three measurement methods were introduced to clarify the smoke characteristics, i.e. various gas concentrations, smoke density and thermophoretic sampling with transmission electron microscopy (TEM). The yield of carbon dioxide and the consumption of oxygen were proportional to the heat release rate of pool fires, but there is no trend on carbon monoxide emission. Smoke density of turbulent flames was exponentially increased with the heat release rate. The morphology of the soot particle was investigated to address the degree of soot maturing. The results show that the similar smoke morphology between an inverse jet flame and a pool fire exists despite of different combustion controlling mechanisms.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.3
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• pp.589-597
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• 1992

The effect of pressure on soot formation in premixed propane-air combustion is investigated at high pressures over the pressure range of 1 to 5 MPa by using a specially designed constant volume combustion bomb. The combustiom chamber of disk type with eight spark plugs located on the circumference at an interval of 45deg is 100mm in diameter by 14mm thick. The end gases are compressed to high pressures by the eight converging flames. The soot volume fraction in the chamber center during the final stage of combustion at the highest pressure is measured by the in-situ laser extinction technique, and the burnt gas temperature during the same period is measured by the two-color method. It is found that the soot yield rises with 50 to 100% for the respective equivalence ratio range of 1.9-2.2 at an interval of 0.1 when the combustion pressure is increased from 1 to 5 MPa, and that the turbulent flames decrease in the soot yield as compared with the laminar flames because the burnt gas temperatures increase with the drop of heat loss.

• Fire Science and Engineering
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• v.33 no.5
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• pp.13-18
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• 2019

In this study, the soot formation characteristics of Jet-A1 liquid fuel droplet flames were investigated by measuring the soot concentration under atmospheric conditions similar to the working environment of the Korea Space Launch Vehicle (KSLV) To obtain the desired atmospheric conditions, the oxygen concentration in the combustion chamber was maintained at 30% and the pressure was varied between 0.1 and 0.06 MPa. The full-field light extinction technique was used to measure the concentration of soot particles generated by applying the identical to 2-mm-diameter Jet-A1 fuel droplets. The soot concentration of the Jet-A1 droplet flames was the highest in the nitrogen-substituted atmosphere and the lowest in the carbon dioxide-substituted atmosphere, despite the pressure. the pressure was decreased the measured soot concentrations reduced as a function of Pⁿ.

• Journal of Hydrogen and New Energy
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• v.20 no.2
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• pp.133-141
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• 2009

본 논문에서는 전기자동차의 고전압 시스템의 안전성을 확보하기 위한 법규 규제안 생성 방법론을 제시하였다. 법규가 기술적으로 모든 영역을 빠뜨리지 않고 정의하고 있는지를 파악하기 위한 방법으로 법규분포분석법(Regulation Distribution Analysis Method)과 법규 완전도 분석법(Regulation Completeness Analysis Method)을 제시하였다. 자동차 설계와 생산에 있어서 법규/규제는 중요한 이슈가 되고 있다. 원칙적으로 법규는 자동차 승객과 환경을 보호하는 목적으로 생성되고, 이윤 추구 중심의 시장에서 놓칠 수 있는 기술적 항목들을 규제할 수 있도록 한다. 매연 배출 정도, 매연 모니터링 시스템, 전기 안전성과 같은 항목이 그 예이며, 향후 연료전기자동차 양산을 앞두고는 고전압 안전성과 관련된 규제 또한 필요하게 될 것으로 파악된다. 그러나 규제 항목에서 미정의된 부분이 있는지를 확인하는 체계적인 방법이 없어 본 논문에서는 기술적인 파라미터를 중심으로 규제항목을 검토하는 방법론을 제시하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.1
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• pp.1-8
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• 2004

An study has been performed with axisymmetric coflow diffusion flames to investigate the influence of air-side fuel side dilution and initial preheated temperature on the soot formation in methan/air flames. Soot quantities are determined by using PLII(Planar Laser Induced Incandescence), such a $C_2$H$_2$ major species(CH$_4$, $O_2$, $N_2$) and temperature are simulated by chemkin code. The numerical analysis was performed with transport properties and detailed reaction mechanisms m axisymmetric coflow diffusion flames. The study of how flame temperature and $N_2$ dilution of air and fuel side influence the soot concentrations is focused. Soot concentrations results on PLII show that preheated temperature contributes to an increase in the soot volume fraction, and soot formation Is more productive to air side dilution than to fuel side dilution. $C_2$H$_2$ concentrations have a similar tendency to soot concentrations.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.7
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• pp.889-898
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• 2003

The soot yield is studied by a premixed propane-oxygen-inert gas combustion in a specially designed disk-type constant-volume combustion chamber to investigate the effect of turbulence on soot formation. Premixtures are simultaneously ignited by eight spark plugs located on the circumference of chamber at 45 degree intervals in order to observe the soot formation under high pressures and high temperatures. The eight flames converged compress the end gases to a high pressure. The laser schlieren and direct flame photographs for observation field with 10 mm in diameter are taken to examine into the behaviors of flame front and gas flow in laminar and turbulent combustion. The soot volume fraction in the chamber center during the final stage of combustion at the highest pressure is measured by the in situ laser extinction technique and simultaneously the corresponding burnt gas temperature by the two-color pyrometry method. It is found that the soot yield of turbulent combustion decreases in comparison with that of laminar combustion because the burnt gas temperature increases with the drop of heat loss.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.10
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• pp.2712-2723
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• 1994

Numerical simulation of an axisymmetric ethylene-air jet diffusion flame has been carried out in order to investigate flame dynamics and soot formation. The model solves the time-dependent Navier-Stokes equations and includes models for soot formation, chemical reaction, molecular diffusion, thermal conduction, and radiation. Numerically FCT(Flux Corrected Transport) and DOM(Discrete Ordinate Method) methos are used for convection and radiation trasport respectively. Simulation was conducted for a 5 cm/sec fuel jet flowing into a coflowing air stream. The maximum flame temperature was found to be approximately 2100 K, and was located at an axial position of approximately 5 cm from the base of the flame. The maximum soot volume fraction was about $7{\times}10^{-7}$, and was located within the high temperature region where the fuel mole fraction ranges from 0.01 to 0.1. The buoyancy-driven low-frequency(12~13 Hz) structures convected along the outer region of the flame were captured. In case without radiation trasport, the maximum temperature was higher by 150 K than in case with radiation. Also the maximum soot volume fraction reached about $8{\times}10^{-6}$. As the the hydrocarbon fuel forms many soot particles, the radiation transport becomes to play a more important role.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.1-9
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• 2001

The soot yield has been studied by a premixed propane-oxygen-inert gas combustion in a specially designed disk-type constant-volume combustion chamber to investigate the effects of pressure, temperature and turbulence on soot formation. Premixtures are simultaneously ignited by eight spark plugs located on the circumference of chamber at 45 degree intervals in order to observe the soot formation under high pressures. The eight flames converged compress the end gases to a high pressure. The laser schlieren and direct flame photographs for observation field with 10 mm in diameter are taken to examine into the behaviors of flame front and gas flow in laminar and turbulent combustion. The soot volume fraction in the chamber center during the final stage of combustion at the highest pressure is measured by the in situ laser extinction technique and simultaneously the corresponding burnt gas temperature by the two-color pyrometry method. The pressure and temperature during soot formation are changed by varying the initial charge pressure and the volume fraction of inert gas compositions, respectively. It is found that the soot yield increases with dropping temperature and rising pressure at constant equivalence ratio, and that the soot yield of turbulent combustion decreases in comparison with that of laminar combustion because the burnt gas temperature increases with the drop of heat loss.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.68-75
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• 2005

By utilizing a semi-empirical soot model, the applicability of the laminar flamelet concept fur simulating the formation and oxidation of soot in the laminar diffusion flame has been studied. The source terms for two transport equations of the soot formation and oxidation are calculated in the mixture fraction/scalar dissipation rate space for laminar flamelets and stored in a library. In this study, emphasis is given to the interaction associated with radiation and soot formation. The radiative heat loss is obtained by solving the radiative transfer equation using the unstructured grid finite volume method with the WSGGM. The calculated temperatures and soot volume fractions agree relatively well with the experimental data and the previous numerical results of Kaplan et al. using the detailed chemistry.

• Journal of ILASS-Korea
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• v.22 no.2
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• pp.80-86
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• 2017

The soot formation characteristics of various alkane-based single fuel droplets were studied in this work. Also, This study was performed to provide the database of the soot behavior and formation of alkane-based single fuel droplet. The experimental conditions were set to 1.0 atm of ambient pressure ($P_{amb}$), 21% of oxygen concentration ($O_2$) and 79% of nitrogen concentration ($N_2$). Combustion and soot formation of single fuel droplet was visualized by visualization system with high speed camera. At the same time, ambient pressure, oxygen concentration and nitrogen concentration were maintained by ambient condition control system. Soot formation characteristics was analyzed and compared on the basis of intensity ratio ($I/I_0$) of background image. The results of toluene fuel droplet showed the largest soot generation. Soot volume fraction ($f_v$) was almost the same under the identical fuel types regardless of various initial droplet diameter ($d_0$) since thermophoretic flux was not much changed under the same ambient conditions.