• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.814-819
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• 2017

The objective of this paper is to observe effects of an ignition position and time on the ignition transition. A gaseous oxygen and liquid kerosene are used for propellants with the shear-coaxial injector. In order to study the ignition delay time and combustion instability intensity, the pressure transducer was used. The ignition position was changed with the injector spacer. Sequences except the igniter operation time were fixed to compare the ignition time only. Initial pressure peak and ignition delay time increased as the ignition time was delayed. Also, the unstable flame development zone was detected as the igniter was away from the injector.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.85-90
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• 2018

The objective of this paper is to observe effects of ignition position and time on ignition transition. A gaseous oxygen and liquid kerosene mixture is used as propellant with a shear-coaxial injector. In order to study the ignition delay time and combustion instability intensity, the pressure transducer was used. Sequences, excepting igniter operation time, were fixed to compare the ignition time only. Initial pressure peak and ignition delay time increased as the ignition time was delayed. Additionally, an unstable flame development zone was detected when the igniter was away from the injector.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.04a
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• pp.1-1
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• 2000

액체로켓엔진에 있어서 연소실로 공급된 추진제의 안정적인 점화를 위해 추진제 공급의 선점 시간을 결정하기 위한 실험이 수행되었다. 사용된 추진제는 Jet A-1과 액체 산소이고 추진제의 공급은 가압 방식이다. 135$^{\circ}$의 각을 갖고 배열된 인젝터는 FOOF 타입의 비동류형 충돌형 인젝터이고 연소실 압력이 200psi가 되도록 설계되었다. 현재의 실험은 점화원으로서 TEAL(triethylaluminum)을 사용하여 쿼드렛 타입의 점화기의 안정적 점화 여부를 검증하는 것도 포함된다. 점화 특성 파악을 위해 인젝터 상류의 매니폴드 압력, 연소실 압력이 측정되었고 점화 과정 및 정상 상태로의 천이 과정에 대한 간접적 증거로서 화염 길이가 측정되었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.996-999
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• 2011

The flow and combustion dynamics in the ignition and ramjet sustainer phase of an integrated rocket-ramjet(IRR) engine are investigated. The physical model includes the entire engine flowpath, from the freestream in front of the inlet to the exit of the exhaust nozzle. The flowfield obtained from a rocket booster study is used as the initial condition for the present analysis, so that the complete operation history of the engine can be obtained. The analysis for the primary factor governing flame propagation during the ignition and the key mechanisms for driving and sustaining the flow oscillations are performed.

• Journal of Energy Engineering
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• v.13 no.4
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• pp.311-318
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• 2004

In the present study, the combustion characteristics of methane and hydrogen-supplemented methane as alternative fuels for automotive vehicles were investigated at various hydrogen substitution rate, ignition position and ignition methods in a CVCC. The main results obtained from the study can be summarized as follow. In case of center ignition and neat methane-air mixture, the flame propagation processes are propagated with an elliptical shape, but they are changed an instable elliptical shape flame with very regular cells and higher velocity by increasing the hydrogen supplement rate. In case of side, 0.5R ignition and neat methane-air mixture, the flame propagation processes are propagated with an instable elliptical shape flame, but they are changed from an instable elliptical shape to wedge shape flame with very irregular cells and higher velocity by increasing the hydrogen supplement rate. Although the flame propagation shape with ignition position and ignition devices was not differ, the flame area of MSCDI device was a little larger than it of CDI device at the same time.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.367-370
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• 2011

A high-resolution numerical study is carried out to investigate the transient process of the combustion and the shock-train developments in an ethylene-fueled direct-connect dual-mode scramjet combustor. Air-throttling is then applied at the expansion part of the combustor to provide mass addition to block the flow to subsonic speed, hence to enhance the fuel-air mixing and ignition. Present simulation shows the detailed results for the better understanding of transient processes of the operation regimes in the dual-mode scramjet combustor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.692-695
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• 2001

The EMFG(Extended Mark Flow Graph) is not only a powerful tool to. designing the discrete-event system conceptually or specifically but also a good representation tool for implementing the system directly. We present a transitions-firing process and automatic changes of the number of marks in each box as a firing determination algorithm with the incident matrix and the state transition equation. The convenient analysis and design of a system as well as Computer Aided Design is possible because the operations of an EMFG ran be represented in the mathematical analysis with ease.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2010.04a
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• pp.59-63
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• 2010

Seven different size of orifice were applied in a constant volume combustion chamber for evaluating the effects of torch-ignition on combustion. The initial flame development and flame propagation were analyzed by the mass fraction burn and combustion enhancement rate. The combustion pressures were measured to calculate the mass fraction burn and the combustion enhancement rates. In addition, the flame propagations were visualized by the shadowgraph method for the qualitative comparison. The result showed that the combustion pressure and mass burned fraction were increased when using the torch-ignition device. The combustion enhancement rates of torch-ignition cases were improved in comparison with conventional spark ignition. Finally, the visualization results showed that the torch-ignition induced faster burn than conventional spark ignition due to the earlier transition to turbulent flame and larger flame surface, during the initial stage.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.981-984
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• 2011

A high-resolution numerical study is carried out to investigate the transient process of the combustion and the shock-train developments in an ethylene-fueled direct-connect dual-mode scramjet combustor. Following the fuel injection, air-throttling is applied at the expansion part of the combustor to provide mass addition to block the flow to subsonic speed. The ignition occurs several ms later when the fuel and air are mixed sufficiently. The pressure build up by the combustion leads to the shock train formation in the isolator section that advances to the exit of the intake nozzle. Then, the air-throttling is deactivated and the exhaust process begins and the situation before the air-throttling is restored. Present simulation shows the detailed processes in the dual-mode scramjet combustor for better understanding of the operation regimes and characteristics.