• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.101-103
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• 2012

Characteristic of aluminum ignition under high temperature and high pressure is studied using lasers. The laser ablation method is used to generate aluminum particles exposed to a high pressure by using a nanosecond pulsed laser where the range of ablation pressure varies between 0.35 and 2.2 GPa. A $CO_2$ laser is used to supply radiative heat to the aluminum target surface for providing high temperature ranging between 5000~9300 Kelvin. The ignition is confirmed using spectroscopy analysis of AlO vibronic band 484 nm wavelength. Also the radiative temperature is measured in various high pressure range for tracing the ignition temperature in high pressure conditions.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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• pp.73-82
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• 2001

The characteristics of the catalytically supported thermal combustion with Pd-based catalyst using the bench scale high pressure combustor has been investigated up to 7 atm. The emission of $NO_{\chi}$ depends on the preheating temperature and the excess air ratio. Most $NO_{\chi}$ emission seems to come from the pre-burner for the preheating of the inlet gas. Decreasing excess air ratio in the inlet gas below 1.5 results in the stable catalytically supported thermal combustion in the post combustion region while the $NO_{\chi}$ emission increased up to 15 ppm. Further, the increase of the pressure shows the dramatic increase of the emission CO and THC. However, the $NO_{\chi}$ emission decreased slightly due to the lower combustion temperature at the high pressure.

• 한국세라믹학회지
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• 제37권5호
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• pp.444-452
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• 2000

Dense composites of titanium matrix and Al2O3 matrix with reinforcements of carbon or titanium carbide fibers were successfully fabricated by high-pressure self-combustion sintering method or combustion reacton under 30 MPa of uniaxial pressure with an aid of external heating in vaccum. It was found that the fibers were uniformly distributed in the matrix, and aligned in a phase perpendicular to the pressure axis. As a moel ratio of Ti/C or reaction time increased, the density of Ti-matrix composite increased Micro pores around fibers could be removed by using clean carbon fibers without sizing agent on their surface. The evolution of carbide fibers from carbon fibers was observed. The composition of the various phases around fibers were analyzed.

• 한국분무공학회지
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• 제5권4호
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• pp.66-71
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• 2000

The present study is mainly motivated to investigate the vaporization, auto-ignition and combustion processes in the high-pressure engine conditions. The high-pressure vaporization model is developed to realistically simulate the spray dynamics and vaporization characteristics in high-pressure and high-temperature environment. The interaction between chemistry and turbulence is treated by employing the Representative Interactive Flamelet (RIF) Model. The detailed chemistry of 114 elementary steps and 44 chemical species is adopted for the n-heptane/air reaction. In order to account for the spatial inhomogeneity of the scalar dissipation rate, the multiple RIFs are introduced. Numerical results indicate that the RIF approach together with the high-pressure vaporization model successfully predicts the ignition delay time and location as well as the essential features of a spray ignition and combustion processes.

• 한국분무공학회지
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• 제10권4호
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• pp.16-25
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• 2005

The present study is mainly motivated to investigate the vaporization, auto-ignition and combustion processes in high-pressure engine conditions. In order to realistically simulate the dimethyl ether (DME) spray dynamics and vaporization characteristics in high-pressure and high-temperature environment, the high-pressure vaporization model is utilized. The interaction between chemistry and turbulence is treated by employing the Representative Interaction Flamelet(RIF) model. The detailed chemistry of 336 elementary steps and 78 chemical species is used for the DME/air reaction. Numerical results indicate that the RIF approach, together with the high-pressure vaporization model, successfully predicts the essential feature of ignition and spray combustion processes.

• 한국자동차공학회논문집
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• 제17권4호
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• pp.79-85
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• 2009

Low temperature combustion regime for the simultaneous reduction of nitrogen oxides ($NO_x$) and paticulate matter (PM) is demonstrated in single cylinder engine at various operating parameters, such as EGR rate, injection timing, EGR temperature, amount of fuel and swirl rate. Low temperature combustion is accomplished by high exhaust gas recirculation (EGR) rate in this study. Generally, the emission of $NO_x$ almost completely disappears and PM significantly increases in the first decreasing regime of oxygen concentration but after peaking about 10~12% oxygen concentration, PM then decreases regardless of fuel injection quantity. Low temperature combustion regime was extended by low EGR temperature, high injection pressure and low amount of fuel.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.75-78
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• 2006

Disposal of highly toxic wastes like polychlorinated biphenyls (PCBs) is very difficult. These substances create a growing mountain of problematic waste that has to be disposed properly. Conventional technologies that are based on common burning(rotary kiln, ${\sim}1100^{\circ}C$) and plasma technology(${\sim}10000^{\circ}C$) do not satisfy important conditions. for example, complete combustion of the toxic waste and the price of waste disposal. The combustor like a rocket engine is operated at relatively high pressure(${\sim}15$ bar) and relatively high temperature(>$3000^{\circ}C$) that are ideal for the complete destruction of extremely toxic substances. In this study, test compound($_o-DCB$) was dissolved in kerosine with a concentration of 10%. Pure gas oxygen was used as an oxidant. Analysis showed that the destruction efficiency achieved for ${o}-DCB$ was 99.9999% or better. The results show that a combustor based on liquid propllant rocket technology is a validated tool for the disposal of highly toxic waste, and a good alternative technology when applied to the destruction of extremely toxic wastes.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2971-2976
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• 2008

Recently, there has been growing interest in the oxyfuel combustion cycle since it enables high-purity CO2 capture with high efficiency. However, the oxyfuel combustion cycle has some important issues regarding to its performance such as the requirement of water recirculation to decrease a turbine inlet temperature and proper combustion pressure to enhance cycle efficiency. The purpose of the present study is to analyze performance characteristics of the oxyfuel combustion cycle with different turbine inlet temperatures and combustion pressures. It is expected that the turbine inlet temperature improves cycle efficiency, on the other hand, the combustion pressure has specific value to display highest cycle efficiency.

• 대한기계학회논문집B
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• 제22권11호
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• pp.1582-1590
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• 1998

Combustion-driven oscillations in a surface burner have been investigated to clarify their characteristics. A model combustor is made and the oscillation frequencies are measured for various dimensions of the combustor. It is found that there are two modes of oscillations; one is the 'acoustic mode' at high frequencies, associated with the acoustic mode of the combustion system and the other is the 'combustion mode' at low frequencies around 100 Hz, associated with the instability of the flame. Acoustic mode is excited when the surface burner is placed where the phase of particle velocity leads that of acoustic pressure by $90^{\circ}$, for all the combustion conditions. Combustion mode is driven at high combustion rate by the lift of unstable flame near the lower limit of the combustible equivalence ratio. Combustion mode is greatly influenced by the inlet temperature of the premixed gas. When the inlet temperature is very high, the combustion mode does not occur.

• 오토저널
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• 제3권3호
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• pp.39-48
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• 1981

The combustion phenomena of the stratified charged model combustion chamber under the initial conditions of the room temperature and the atmospheric pressure were investigated by using pressure record and high speed Schliern motion picture in comparison with that of the uniformly charged case. The results show that the total burning time is strongly dependent on the turbulent spouting flame jet speed which promotes the combustion process inside the chamber, and the pressure rise-up of stratified charged combustion is rather faster and higher than that of uniformly charged combustion, which can be resulted in the energy saving.