• 한국안전학회지
• /
• 제28권2호
• /
• pp.49-54
• /
• 2013

The autoignition temperature(AIT) is important index for the safe handling of flammable liquids which constitute the solvent mixtures. This study measured the AITs and ignition delay time for n-Decane and Acetic acid system by using ASTM E659 apparatus. The AITs of n-Decane and Acetic acid which constituted binary system were $212^{\circ}C$ and $512^{\circ}C$, respectively. The experimental AITs of n-Decane and Acetic acid system were a good agreement with the calculated AITs by the proposed equations with a few A.A.D.(average absolute deviation). And n-Decane and Acetic acid system was shown the minimum autoignition temperature behavior(MAITB).

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
• /
• pp.24-32
• /
• 2002

The autoignition and subsequent flame propagation of initially nonpremixed turbulent system have been numerically analyzed. The unsteady flamelet modeling based on the RIF (Representative Interactive Flamelet) concept has been employed to account for the influences of turbulence on these essentially transient combustion processes. In this RIF approach, the partially premixed burning, diffusive combustion and formation of pollutants(NOx, soot) can be consistently modeled by utilizing the comprehensive chemical mechanism. To treat the spatially distributed inhomogeneity of scalar dissipation rate, the multiple RIFs are employed in the framework of EPFM(Eulerian Particle Flamelet Model) approach. Computations are made for the various initial conditions of pressure, temperature, and fuel composition. The present turbulent combustion model reasonably well predicts the essential features of autoignition process in the transient gaseous fuel jets injected into high pressure and temperature environment.

• 한국자동차공학회논문집
• /
• 제10권5호
• /
• pp.81-89
• /
• 2002

The autoignition and subsequent flame propagation of initially nonpremixed turbulent system have been numerically analyzed. The unsteady flamelet modeling based on the RIF (representative interactive flamelet) concept has been employed to account for the influences of turbulence on these essentially transient combustion processes. In this RIF approach, the partially premixed burning, diffusive combustion and formation of pollutants(NOx, soot) can be consistently modeled by utilizing the comprehensive chemical mechanism. To treat the spatially distributed inhomogeneity of scalar dissipation rate, the multiple RIFs are employed in the framework of EPFM(Eulerian particle flamelet model) approach. Computations are made for the various initial conditions of pressure, temperature, and fuel composition. The present turbulent combustion model reasonably well predicts the essential features of autoignition process in the transient gaseous fuel jets injected into high pressure and temperature environment.

• 한국화재소방학회:학술대회논문집
• /
• 한국화재소방학회 2008년도 춘계학술논문발표회 논문집
• /
• pp.100-103
• /
• 2008

Autoignition suppression of hydrogen/air premixed mixtures by $CF_3CHFCF_3$(HFP) was investigated computationally. Numerical simulation was performed in isobaric and homogeneous system to evaluate the induction times. The detailed chemistry of 93 species and 817 reaction mechanism was introduced for hydrogen/air/HFP mixtures. The results shows the similar concentrations for the major reactants such as hydrogen and oxygen during autoignition while water vapor produced at the ignition temperature was decomposed later, which leaded to the shoulder on the concentration of H, OH and O radical with time. The fluorine included from HFP was converted mainly to stable HF and the carbon was formed to various species, CF2, CF2O, CO etc. More details of chemical effects of HFP addition will be investigate with sensitivity analysis in the near future.

• 한국자동차공학회논문집
• /
• 제5권1호
• /
• pp.15-26
• /
• 1997

The present study is mainly motivated to numerically simulate the autoignition and combustion process of a diesel spray in RCM and effects of design parameters on combustion and engine performance in the DI diesel engine using EGR. In case of the burning spray in RCM, special emphasis is given to the autoignition process coupled with the fluid mechanics and chemical reaction. Computations are carried out for a wide range of operating condition in terms of temperature, concentration of oxygen and carbon dioxide of the intake gas in the DI diesel engine. Numerical results indicate that the mixing process along the edges of spray jet has a crucial role for autoignition and combustion process. Temperature and concentration of O2 and CO2 of intake gas significantly influence the combustion characteristics and engine performance in the diesel/EGR environment.

• 한국화재소방학회논문지
• /
• 제27권5호
• /
• pp.64-69
• /
• 2013

가연성 혼합물의 최소자연발화온도는 가연성액체의 안전한 취급을 위해서 중요한 지표가 된다. 본 연구에서는 ASTM E659 장치를 이용하여 가연성 혼합물인 n-Propanol과 Formic acid 계의 최소자연발화온도와 발화지연시간을 측정하였다. 2성분계를 구성하는 순수물질인 n-Propanol과 Formic acid의 최소자연발화온도는 각 각 $435^{\circ}C$와 $498^{\circ}C$로 측정되었다. 그리고 측정된 n-Propanol과 Formic acid 계의 최소자연발화온도는 제시된 식에 의한 예측값과 작은 평균절대오차에서 일치하였다. 그리고 n-Propanol과 Formic acid 계는 일부 혼합 조성에서 두 개의 순수물질 가운데 낮은 AIT보다 낮게 측정된 최소자연발화온도거동(MAITB, Minimum Autoignition Temperature Behavior)을 보이고 있다.

• 대한기계학회논문집B
• /
• 제23권6호
• /
• pp.778-787
• /
• 1999

In this study, the autoignition process of liquid fuel, injected into hot and stagnant air in a 2-D axisymmetric confined cylindrical combustor, has been investigated. Eulerian-Lagrangian scheme was adopted to analyze the two-phase flow and combustion. The unsteady conservation equations were used to solve the transition of the gas field. Interactions between two phases were accounted by using the particle source in cell (PSI-Cell) model, which was used for detailed consideration of the finite rates of transports between phases. And infinite conduction model was adopted for the vaporization of droplets. The results have shown that the process of the autoignition consists of heating up of droplets, vaporization, mixing and ignition. The ignition criteria could be determined by the temporal variations of temperature, reaction rate and species mass fraction. And the effects of various parameters on ignition phenomena are examined. These have shown that the increasing the reaction rate and/or the vaporization rate can reduce the ignition delay time.

• 한국화재소방학회논문지
• /
• 제23권5호
• /
• pp.50-56
• /
• 2009

폭발한계와 최소자연발화온도는 가연성 물질의 화재 및 폭발 위험성을 결정하는데 중요한 특성으로 이용된다. 에틸렌의 안전한 취급을 위해 에틸렌의 폭발한계와 최소자연발화온도를 고찰하였다. 에틸렌의 폭발하한계와 상한계는 공기 중에서 각 각 2.6vol%와 36vol%를 추천하며, 최소자연발화온도는 전면 가열인 경우는 $420^{\circ}C$, 국소 고온표면인 경우는 약 $800^{\circ}C$를 추천한다. 또한 에틸렌의 폭발한계의 온도 및 압력의 존성에 대한 새로운 예측식을 제시하였으며, 제시된 식에 의한 예측값은 문헌값과 일치하였다.

• 오토저널
• /
• 제15권1호
• /
• pp.28-36
• /
• 1993

Present-day there are two of theories which have considerable scientific support to explain the knock phenomenon in S.I. engine, the detonation theory and the autoignition theory. But they still have some problems to explain effects of knock parameters, i.e.. compression ratio, spark timing, mixture quality, engine speed, ect, on knocking process in S.I. engine. Accordingly, it is essential to find out whish is more adequate theory of two and to develop the method of analyzing knock phenomenon, that is the aim of this paper. The Authors develop the method of predicting transient temperature and pressure at the end-gas zone during the combustion period and analyze knocking process by this method based on the knock theories. The caluculated values based on the autoignition theory show reasonablly correct relations between knock parameters and knock process but there is no evidence of knock occurred by detonation theory through the calculation according to the all parameters. The authors find out that the autoignition theory is more adequate than detonation theory to analyze knocking process in S.I. engine.

• International Journal of Automotive Technology
• /
• 제6권2호
• /
• pp.133-139
• /
• 2005

In this study, a three-dimensional transient simulation with a knock model was performed to predict knock occurrence and autoignition site in a heavy-duty LPG engine. A FAE (Flame Area Evolutoin) premixed combustion model was applied to simulate flame propagation. The coefficient of the reduced kinetic model was adjusted to LPG fuel and used to simulate autoignition in the unburned gas region. Engine experiments using a single-cylinder research engine were performed to calibrate the reduced kinetic model and to verify the results of the modeling. A pressure transducer and a head-gasket type ion-probe circuit board were installed in order to detect knock occurrences, flame arrival angles, and autoignition sites. Knock occurrence and position were compared for different piston bowl shapes. The simulation concurred with engine experimental data regarding the cylinder pressure, flame arrival angle, knock occurrence, and autoignition site. Furthermore, it provided much information about in-cylinder phenomena and solutions that might help reducing the knocking tendency. The knock simulation model presented in this paper can be used for a development tool of engine design.