• 한국연소학회:학술대회논문집
• /
• 2012.04a
• /
• pp.279-281
• /
• 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.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.1
• /
• pp.75-82
• /
• 2011

The numerical analysis of the reduction of reaction mechanism for the ignition of dimethyl ether (DME) was performed. On the basis of a detailed reaction mechanism involving 79 species and 351 reactions, the peak molar concentration and sensitivity analysis were conducted in a homogeneous reactor model. The reduced reaction mechanism involving 44 species and 166 reactions at the threshold value $7.5{\times}10^{-5}$ of the molar peak concentration was established by comparing the ignition delays the reduced mechanism with those the detailed mechanism. The predicted results of the reduced mechanism applied to the single-zone homogeneous charge compression ignition (HCCI) engine model were in agreement with those of the detailed mechanism. Therefore, this reduced mechanism can be used to accurately simulate the ignition and combustion process of compression ignition engine using DME fuel.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.1704-1709
• /
• 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.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.3
• /
• pp.74-81
• /
• 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.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.4 no.2
• /
• pp.12-20
• /
• 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.

• 한국연소학회:학술대회논문집
• /
• 2014.11a
• /
• pp.215-218
• /
• 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.

• 한국연소학회:학술대회논문집
• /
• 2012.11a
• /
• pp.93-96
• /
• 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.

• Bulletin of the Korean Chemical Society
• /
• v.22 no.3
• /
• pp.303-307
• /
• 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.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.4
• /
• pp.44-49
• /
• 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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1995.11a
• /
• pp.139-144
• /
• 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.