• 제목/요약/키워드: ignition mechanism

검색결과 132건 처리시간 0.022초

축소 반응 메카니즘으로부터 예혼합 화염 및 자발화 계산 (Premixed Flames and Auto-ignition Computations with the Short Chemical Mechanism)

  • 이수각;이기용
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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    • pp.279-281
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    • 2012
  • A short chemical mechanism was developed with the chemical model reduction strategy based on the use of Simulation Error Minimization Connectivity Method(SEM-CM). We examined the accuracy resulting from using this mechanism, as compared with the full mechanism, for premixed flames and auto-ignition of methane-air mixture under high pressures. These comparisons are in good agreement, but it has a little divergence to predict the ignition delay time at high pressure conditions as compared with experiment results.

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디메틸 에테르 착화에 관한 반응기구 축소 연구 (A Study on the Reduction of Reaction Mechanism for the Ignition of Dimethyl Ether)

  • 류봉우;박성욱;이창식
    • 대한기계학회논문집B
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    • 제35권1호
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    • pp.75-82
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    • 2011
  • 디젤의 대체연료인 디메틸 에테르의 반응기구 축소에 관한 수치해석을 수행하였다. 상세반응기구(79 개의 화학종과 351 개의 반응단계)를 기초로, 최대몰농도 해석과 민감도 해석을 균질 반응기 모델에 적용하였다. 축소반응기구는 상세반응기구의 착화지연기간과 비교하여 구축하였는데, 기준값으로 $7.5{\times}10^{-5}$을 적용했을 때 44 개의 화학종과 166 개의 반응단계로 구성된다. 축소반응기구의 계산 정확도를 검증하기 위하여 두 반응기구를 단일영역 균일예혼합 압축착화 엔진모델에 적용하였고, 축소반응기구의 계산결과는 상세반응기구의 결과와 일치하였다. 따라서 본 연구의 축소반응기구는 계산의 정확도의 손실 없이 DME 를 연료로 사용하는 압축착화엔진의 착화 및 연소 과정을 모사하는데 이용될 수 있다.

고속 직분식 디젤 엔진에서의 점화지연시기 예측 (Prediction of Ignition Delay for HSDI Diesel Engine)

  • 임재만;김용래;온형석;민경덕
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.1704-1709
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    • 2004
  • New reduced chemical kinetic mechanism for prediction of autoignition process of HSDI diesel engine was investigated. For precise prediction of the ignition characteristics of diesel fuel, mechanism coefficients were fitted by the experimental results of ignition delay of diesel spray in a constant volume vessel. Ignition delay of diesel engine on various operation condition was calculated based on the new reduced chemical mechanism. The calculation results agreed well with experimental data.

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모사 디젤 화학반응 메커니즘의 각 성분이 화학적 점화 지연 시간에 미치는 영향에 관한 기초 연구 (Fundamental Study on the Chemical Ignition Delay Time of Diesel Surrogate Components)

  • 김규진;이상열;민경덕
    • 한국자동차공학회논문집
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    • 제21권3호
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    • pp.74-81
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    • 2013
  • Due to its accuracy and efficiency, reduced kinetic mechanism of diesel surrogate is widely used as fuel model when applying 3-D diesel engine simulation. But for the well-developed prediction of diesel surrogate reduced kinetic mechanism, it is important to know some meaningful factors which affect to ignition delay time. Meanwhile, ignition delay time consists of two parts. One is the chemical ignition delay time related with the chemical reaction, and the other is the physical ignition delay time which is affected by physical behavior of the fuel droplet. Especially for chemical ignition delay time, chemical properties of each fuel were studied for a long time, but researches on their mixtures have not been done widely. So it is necessary to understand the chemical characteristics of their mixtures for more precise and detailed modeling of surrogate diesel oil. And it shows same ignition trend of paraffin mixture with those of single component, and shorter ignition delay at low/high initial temperature when mixing paraffin and toluene.

램제트 엔진의 점화 천이에 관한 연구 (Ignition Transient Mechanism in an Entire Integrated Rocket Ramjet Engine)

  • 성홍계
    • 한국추진공학회지
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    • 제4권2호
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    • pp.12-20
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    • 2000
  • The numerical analysis, including chemical reaction of an entire ramjet engine is studied to understand the ignition transient mechanism and the dynamic characteristics of the Integrated Rocket Ramjet System comprehensively. Details of how a subsonic combustion environment is established from the supersonic ram air after removal of the inlet port cover, are examined during the ignition transient. Various physical processes are investigated systemically, including ignition, flame propagation, flame dynamics, and vorticity evolution.

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튜브 내 누출되는 고압수소의 격막파열조건에 따른 자발점화 현상 (Self Ignition Phenomena of High Pressure Hydrogen Released into Tube with Diaphragm Rupture Conditions)

  • 임한석;이상윤;이형진;정인석
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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    • pp.215-218
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    • 2014
  • High combustion efficiency of hydrogen could make it an ideal source of green energy in the future. At this time, high pressure vessel is the most reasonable method of storing hydrogen. However, such a high pressurized vessel could pose a critical threat if ruptured. For this reason, it is important to understand the mechanism of hydrogen's self-ignition when a high-pressure hydrogen released into air. This paper presents several visualization images as experimental results using high-speed camera. From the visualization images, the ignition is initiated near rupture disk immediately after failure of disk. And the initial ignition and flame is stronger as a rupture pressure increases. However, this ignition region do not affect the general self-ignition mechanism when a high-pressure hydrogen is released into air through tue after failure of disk.

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파열 압력에 따른 튜브 내 고압 수소 누출에 의한 자발점화 현상 (Spontaneous Ignition of High Pressure Hydrogen Gas released into Tube due to the Burst Pressure Variation)

  • 이형진;김성돈;김세환;정인석
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.93-96
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    • 2012
  • The spontaneous ignition mechanism of high pressure hydrogen gas released into tube is well-deduced from previous studies. However, those results have a limit because the studies have been conducted at low burst pressure of about 10 MPa. In this study, the process or ignition feature are investigated with higher burst pressure of up to 30 MPa through numerical analysis. The results show that the trend of ignition became to be different with a burst pressure. While two reaction regions is important to initiate the ignition when burst pressure is about 10 MPa, the reaction of the core region does not play a role in ignition inside the tube when a burst pressure is above 20 MPa.

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Shock Tube and Modeling Study of the Ignition of Propane

  • 김길영;신권수
    • Bulletin of the Korean Chemical Society
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    • 제22권3호
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    • pp.303-307
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    • 2001
  • The ignition of propane was investigated behind reflected shock waves in the temperature range of 1350-1800 K and the pressure range of 0.75-1.57 bar. The ignition delay time was measured from the increase of pressure and OH emission in the C3H8-O2-Ar system. The relationship between the ignition delay time and the concentrations of propane and oxygen was determined in the form of mass-action expression with an Arrhenius temperature dependence. The numerical calculations were also performed to elucidate the important steps in the reaction scheme of propane ignition using various reaction mechanisms. The ignition delay times calculated from the mechanism of Sung et al.1 were in good agreement with the observed ones.

축소 화학반응 모델링에 의한 탄화수소 연료의 점화지연 특성 (Characteristics of the Ignition Delay for Hydrocarbon Fuels by Reduced Chemical Kinetics Modeling)

  • 김형욱;배상수;민경덕
    • 한국자동차공학회논문집
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    • 제9권4호
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    • pp.44-49
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    • 2001
  • Reduced chemical kinetics mechanism has been derived, which can be applicable for autoignition model of hydrocarbon fuels, and contains 23 reactions and 18 species. The present model is validated with the experimental data, where the ignition delays of several hydrocarbon fuels, such as n-heptane, i-octane, n-decane and DME(dimethylether) are measured as equivalence ratios are varied. Especially, the effects of different fuels on ignition delays can be explained by changing the rate constants of three reactions among the present model. As a result, the proposed model can be applicable to two stage ignition model of Diesel combustion.

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고체추진기관에서 점화현상의 성능해석 연구

  • 김유;류계열
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 1995년도 제5회 학술강연회논문집
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    • pp.139-144
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    • 1995
  • The main purpose of igniter is sure ignition of main propellant at desired ignition delay times. Since ignition mechanism of solid rocket propellant involves so many complicated physical and chemical phenomena, it is almost impossible to predict ignition behavior with pure analytical means. In this study, one dimensional and unsteady ignition transient phenomena in solid rocket was analyzed by finite volume method. In analysis, assumption was made that ignition occurs when propellant surface temperature reaches to it's auto-ignition temperature.

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