• Title/Summary/Keyword: autoignition

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Conditional Moment Closure Modeling in Turbulent Nonpremixed Combustion (난류확산연소에서의 Conditional Moment Closure Modeling)

  • Huh, Kang-Y.
    • Journal of the Korean Society of Combustion
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    • v.5 no.2
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    • pp.9-17
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    • 2000
  • A brief introduction is given on the conditional moment closure model for turbulent nonpremixed combustion. It is based on the transport equations derived through a rigorous mathematical procedure for the conditionally averaged quantities and appropriate modeling forms for conditional scalar dissipation rate, conditional mean velocity and reaction rate. Examples are given for prediction of NO and OR in bluffbody flames, soot distribution in jet flames and autoignition of a methane/ethane jet to predict the ignition delay with respect to initial temperature, pressure and fuel composition. Conditional averaging may also be a powerful modeling concept in other approaches involved in turbulent combustion problems in various different regimes.

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A Study on Autoignition of Fish Meal with Change of Ambient Temperature (주위온도 변화에 따른 어분의 자연발화에 관한연구)

  • 목연수;최재욱
    • Journal of the Korean Society of Safety
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    • v.7 no.1
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    • pp.47-56
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    • 1992
  • Spontaneous ignition charactenstics for fish meal were observed by performing experiments at constant ambient temperature and varying the ambient temperature sinusoidally. As the results of the experiments at a constant ambient temperature, the critical spontaneous ignition temperature of the sample for large, intermediate and small vessels was 170.5$^{\circ}C$, 177.5$^{\circ}C$ and 188.5$^{\circ}C$, respectively. The critical spontaneous ignition temperature decreased as the sample vessel size increased. Apparent activation energy of used fish meal calculated from the Frank-Kamenetskii's thermal ignition theory was 37.60Kcal/mol. In case of varying the ambient temperature sinusoidally, the amplitudes of temperature were 1$0^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$ respectively with the period in each amplitude 1hr, 2hrs and 3hrs. The results showed that the critical spontaneous ignition temperatures at the varied amplitudes of temperature were lower than that at the constant anbient temperature and increased as the amplitude increased. At the same amplitude, the critical spontaneous ignition temperature increased with the period.

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A Study on Autoignition Characteristics of Methylmethacrylate-butadiene-styrene Copolymer (MBS 공중합물의 자연발화 특성에 관한 연구)

  • 목연수;최재욱
    • Journal of the Korean Society of Safety
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    • v.16 no.3
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    • pp.83-88
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    • 2001
  • This study was preformed by measuring the minimum ignition temperature of MBS according to the change of sample vessel size and the minimum ignition temperature of MBS dust cloud The minimum ignition temperature of MBS product decreased as the vessel size was large, and it was obtained in the range from $120.5^{\circ}C$ to $94.5^{\circ}C$ and the apparent activation energy was obtained with 32.94Kcal/mol. The minimum ignition temperature of MBS dust cloud was measured by using Godbert-Greenwald furnace and it was obtained at $407^{\circ}C$ with the sample of 0.4g in the air and the ignition of dust cloud was not occurred below 13% oxygen concentration.

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The Investigation of Compatibility of Combustible Characteristics for n-Tridecane (노말트리데칸의 연소특성치의 적정성 고찰)

  • Ha, Dong-Myeong
    • Journal of the Korean Society of Safety
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    • v.27 no.3
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    • pp.83-88
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    • 2012
  • For the safe handling of n-tridecane, the lower flash points and AITs(auto-ignition temperatures) by ignition delay time were experimented. Also lower explosion limits by the lower flash points were calculated. The lower flash points of n-tridecane by using closed-cup tester were experimented $92^{\circ}C$ and $96^{\circ}C$. The lower flash points and fire point of n-tridecane by using open cup tester were experimented 100 oC and 103 oC, respectively. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 apparatus for n-tridecane. The experimental AIT of n-tridecane was 223 oC. The calculated lower explosion limit by using measured lower flash point 92 oC for n-tridecane was 0.6 Vol.%.

A Study on Fire and Explosion Accident Cause in Regenerated Thermal Oxidizer (축열식 소각로의 화재.폭발 사고원인 규명 연구)

  • Lee, Keun-Won;Ma, Byung-Chol;Hwang, Soon-Yong
    • Journal of the Korean Institute of Gas
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    • v.11 no.4
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    • pp.7-11
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    • 2007
  • There has been a report of fire and explosion accident in regenerated thermal oxidizer (RTO). This paper was to investigate accident causes of RTO in the resin re-treatment process. The experiments carried out physicochemical properties and thermal stability analyses by using flash point tester, flammable range apparatus, autoignition tester, GC/MSD and thermal screening unit. We inferred causes of fire and explosion from the regenerated thermal oxidizer to prevent an accident of its process.

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The Measurement of Combustible Properties of Acetic Anhydride for the Compatibility of MSDS (MSDS 적정성을 위한 아세틱안하이드리드의 연소특성치 측정)

  • Ha, Dong-Myeong
    • Journal of the Korean Society of Safety
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    • v.29 no.4
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    • pp.85-90
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    • 2014
  • For the safe handling of acetic anhydride, this study was investigated the explosion limits of acetic anhydride in the reference data. And the lower flash points, upper flash points, and AITs(auto-ignition temperatures) by ignition delay time were experimented. The lower and upper explosion limits of acetic anhydride by the investigation of the literatures recommended 2.9 Vol% and 10.3 Vol.%, respectively. The lower flash point of acetic anhydride by using Setaflash closed-cup tester was experimented $49^{\circ}C$. The lower flash point acetic anhydride by using Tag and Cleveland open cup tester were experimented $55^{\circ}C$and $62^{\circ}C$, respectively. Also, this study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for acetic anhydride. The experimental AIT of acetic anhydride was $350^{\circ}C$.

Turbulent Combustion Dynamics of Transverse Fuel Injection into a Supersonic Crossflow using DES (DES를 이용한 초음속 유동내 수직 연료분사 유동의 난류 연소 해석)

  • Won, Su-Hee;Jeung, In-Seuck;Choi, Jeong-Yeol
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.334-337
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    • 2008
  • Three-dimensional unsteady reacting flowfield generated by transverse hydrogen injection into a supersonic mainstream are numerically investigated using DES and finite-rate chemistry model. Comparisons are made with experimental results to investigate the turbulent reacting flow physics. The numerical OH distribution describes well the experimental OH-PLIF result, while the numerical ignition delay time shows some disparity due to the restricted available experimental data.

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The Measurement of the Combustible Properties of tert-Butylbenzene for the Improvement of MSDS (Material Safety Data Sheet) (MSDS 개선을 위한 tert-Butylbenzene의 연소특성치의 측정)

  • Ha, Dong-Myeong
    • Fire Science and Engineering
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    • v.31 no.3
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    • pp.25-30
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    • 2017
  • Because of the vertical combustion characteristics of combustible substances, accurate substance safety information for their safe use, handling and transportation is essential. The flash point, fire point, explosion limits and autoignition temperature (AIT) are important safety parameters which need special attention in chemical plants and laboratories that handle dangerous materials. In this study, tert-butylbenzene which is widely used as an intermediate material in the chemical industry was selected. For the reliability of the flammable properties of tert-butylbenzene, this study was investigated the explosion limits of tert-butylbenzene in the reference data. The flash points, fire points and AITs by the ignition delay time for tert-butylbenzene were experimented. The lower flash points of tert-butylbenzene by using the Setaflash and Pensky-Martens closed-cup testers measured $39^{\circ}C$ and $44^{\circ}C$, respectively. The flash points of tert-butylbenzene by using the Tag and Cleveland open cup testers are measured $51^{\circ}C$ and $54^{\circ}C$. And the fire points of tert-butylbenzene by the Tag and Cleveland open cup testers were $54^{\circ}C$ and $58^{\circ}C$ respectively. The AIT of tert-butylbenzene measured by the ASTM 659E tester was measured as $450^{\circ}C$. The lower explosion limit of $39^{\circ}C$ which measured by the Setaflash flash point tester was calculated to be 0.68 vol%.

Characteristic of Auto Ignition Temperature due to the Mixture Ratio of Ethylene Glycol and Water (Ethylene Glycol과 물의 혼합비에 따른 자연발화온도 특성)

  • Kim, Jung-Hun;Choi, Jae-Wook
    • Fire Science and Engineering
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    • v.30 no.1
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    • pp.24-30
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    • 2016
  • Autoignition characteristic is an important factor of all combustible substances, and a critical determinant in assessing the effectiveness of fire hazard prevention. This study investigated the autoignition characteristic of mixtures of Ethylene Glycol and water using an ASTM D2155 type ignition temperature measuring apparatus. It was possible to get the minimum temperature as $434^{\circ}C$ from 100% Ethylene Glycol within range of $75{\sim}160{\mu}l$. A volume of $100{\sim}125{\mu}l$ of a mixed sample of Ethylene Glycol and water (80 : 20) was ignited at the same temperature ($434^{\circ}C$). Also it was possible to get the auto ignition temperature as $437^{\circ}C$ from a mixed sample of Ethylene Glycol and water (60 : 40) within range of $120{\sim}160{\mu}l$. The instantaneous ignition temperatures determined for $125{\mu}l$ of each of the three samples were $579^{\circ}C$, $595^{\circ}C$ and $611^{\circ}C$, respectively. Both auto ignition temperatures and instantaneous ignition temperatures were increased through the addition of water to the samples.

The Measurement and Prediction of the Combustible Properties of of Benzyl-Alcohol for MSDS (Material Safety Data Sheet) (MSDS (Material Safety Data Sheet)를 위한 벤질알코올 연소특성치의 측정 및 예측)

  • Ha, Dong-Myeong
    • Korean Chemical Engineering Research
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    • v.55 no.2
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    • pp.190-194
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    • 2017
  • The combustion properties for the prevention of the fire and explosion in the work place are flash point, explosion limit, autoignition temperature (AIT) etc.. The using of the corrective combustion properties of the MSDS (Material Safety Data Sheet) of the handling substance for the chemical process safety is very important. For the safe handling of benzyl alcohol which is widely used in the chemical industry, the flash point and the AIT were measured. And, the lower explosion limit (LEL) of benzyl alcohol was calculated by using the lower flash point which obtained in the experiment. The flash points of benzyl alcohol by using the Setaflash and Pensky-Martens closed-cup testers measured $90^{\circ}C$ and $93^{\circ}C$, respectively. The flash points of benzyl alcohol by using the Tag and Cleveland open cup testers are measured $97^{\circ}C$ and $100^{\circ}C$. The experimental AIT of benzyl alcohol by ASTM 659E tester was measured as $408^{\circ}C$. The LEL of benzyl alcohol measured by Setaflash closed-cup apparatus was calculated as 1.17 vol% at $90^{\circ}C$. In this study, it was to possible predict the LEL by using the lower flash point of benzyl alcohol which measured by Setaflash closed-cup tester.