• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.2
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• pp.124-131
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• 1994

자동차엔진의 연소과정에 상사하는 밀폐정적연소실을 주연소실과 대향 2개 부연소실로 분할하고 오리피스로 연결하였다. 이때 부연소실로부터 주연소실로 분출하는 대향분출염 연소에 의한 질소산화물 배출저감특성을 연소방식, 연소실형상 그리고 연료종류를 변경한 수종의 실험으로 조사하였다. 질소산화물농도, 연소실 최고압력, 화염전파과정의 고속도슐리렌사진 가시화를 수행한 결과, 대향분출염 연소방식을 도입하연 연소실의 중앙부공간이 상대적으로 넓은 경우에 고부하운전과 동시에 질소산화물의 배출량도 저감할 수 있었다. 그러나 연료의 종류는 질소산화물생성에 매우 영향이 적었다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.2
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• pp.125-134
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• 2015

This is the third paper on the combustion characteristics of the landfill gas in a constant volume combustion chamber for a large displacement volume commercial engine. It is the first in this series to discuss the effects of the torch device on combustion. The results show that an optimum orifice ratio exists regardless of the torch volume, and a few adverse effects on the combustion are observed for an excessively small orifice ratio. In addition, the torch ignition decreases the initial burn duration, and the decrease in the heat transfer caused by this decreased duration contributes to an increase in the peak combustion pressure. Finally, the torch mostly plays a positive role in shortening the main burn duration when the combustion condition is worsened by a lower methane fraction. Yet, the torch decreases the initial burn duration rather than the main burn as the methane fraction increases.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.2
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• pp.72-79
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• 2003

A numerical calculation was conducted to estimate and to elucidate the role of the radiative heat flux from metal particles(Al, $Al_2O_3$) on the dynamic extinction of solid propellant rocket where the rapid depressurization took place. Anon-linear flame modeling implemented by the residence time modeling for metalized propellant was adopted to evaluate conductive heat flux to the propellant surface. The radiative heat feed back was calculated with the aid of a modified comvustion-flow model as well. The calculation results with the propellant of AP:Al:CTPB=76:10:14 had revealed that the radiative heat flux is approximately 5~6% of total flux at the critical depressurization rate regardless of chamber geometry (open or confined chamber). It was also found that the dynamic extinction in open geometry could be predicted at the depressurization rate about 45% larger with radiative heat feedback than without radiation. Thus, it should be claimed that even a small amount of radiative flux 5~6% could produce a big error in predicting the critical depressurization rate of the metalized propellant combustion.

• Journal of the KSME
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• v.56 no.9
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• pp.54-57
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• 2016

로켓연소기는 수백 개의 분사기로 구성된 연소실에서 연소반응이 발생하게 된다. 이때 구조적인 특성으로 난류유동, 밀도, 온도 등의 변화가 매우 불균일한 3차원적인 분포를 가지게 된다. 이러한 불균일한 분포에 의해 발생되는 압력의 시간변화가 연소기의 고유진동수와 일치될 경우 공진이 발생하게 되어 폭발이 발생하게 된다. 이러한 현상을 연소불안정이라 하고 이글에서는 관련된 연구의 동향을 소개하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.2
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• pp.197-204
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• 2011

RCM is used to clarify the complex phenomena of engine combustion. In order to describe engine combustion, several significant experimental studies are considered. Prediction of the peak pressure is very important since it has a significant influence on engine combustion. In addition, peak-temperature variation can be calculated from the measured peak pressure by using the fundamental thermodynamic relation. When the RCM is in operation, heat transfer occurs through the cylinder wall. Because of this phenomenon, it is difficult to determine the peak pressure without employing the case by case experimental method. The goal of this study is to evaluate the peak pressure analytically. We conduct an experiment to confirm the relationship between the peak pressure and some parameters. Using the results of the peak pressure variation experiment, we develop a general equation that be used to calculate the peak pressure as a function of operation time and compression ratio.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.295-298
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• 2008

In this paper, prototype dynamic modeling scheme to control ramjet propulsion systems were proposed. From the physical understandings of engine system, a typical 2nd-order system model was applied to simulate the dynamic characteristics of fuel supply system. The shock location varience in diffuser to chamber pressure fluctuation is calculated so that the out of phase between two signals was observed.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.51-56
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• 2002

Satellite propulsion system is employed for orbit transfer, orbit correction, and attitude control. The monopropellant feeding system in the low-earth-orbit satellite blowdowns fuel to the thrust chamber. The thrust produced by the thruster depends on fuel amount flowed into the combustion chamber. If the thruster valve be given on-off signal from on-board commander in the satellite, valve will be opened or closed. When the thrusters fire fuel flows through opened thruster valve, instantaneous stoppage of flow in according to valve actuation produces transient pressure due to pressure wave. This paper describes transient pressure predictions of the KOMPSAT-2 propulsion system resulting from latching valve and thrust control valve operations. The time-dependent set of the fluid mass and momentum equations are calculated by MOC.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.7
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• pp.1398-1407
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• 1992

The prediction of heat loss during laminar flame propagation was carried out by measurement of gas pressure and visualization of flame propagation in the constant volume combustion chamber. And to validate the prediction, the instantaneous temperature at wall of combustion chamber was also measured. Consequently, it was found that heat loss was increased according to increasing of maximum flame travel distance, but rate of heat loss for heat release during laminar flame propagation was nearly constant. And heat loss depends on heat transfer area which was contacted the wall by burned gas regardless to spark plug location.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.251-257
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• 2012

This work presents an experimental investigation of NOx emissions according to inlet air temperature (550-660 K), stoichiometric air ratio (${\lambda}$, 1.4-2.1), and elevated pressure (2-5 bar) in a High Press Combustor (HPC) equipped with a double cone burner, which was designed by Pusan Clean Coal Center (PC3). The exhaust-gas temperature and NOx emissions were measured at the end of the combustion chamber. The NOx emissions generally decreased as a function of increasing ${\lambda}$. On the other hand, NOx emissions were influenced by ${\lambda}$, inlet air temperature and pressure of the combustion chamber. In particular, when the inlet air temperature increased, the flammability limit was extended to leaner conditions. As a result, a higher adiabatic temperature and lower NOx emissions could be achieved under these operation conditions. The NOx emissions that were governed by thermal NOx were greatly increased under elevated pressures, and slightly increased at sufficiently low fuel concentrations (${\lambda}$ >1.8).

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1016-1020
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• 2017

This study was conducted to develop a test facility that simulates the combustion instability that occurs in a real-scale liquid rocket combustor. A separate engine head with 3 injectors arranged in a row was designed/manufactured and verified through preliminary tests. The flow rate and spray pattern of the head were confirmed by the cold flow test. Next, propellant spray test and combustion test were carried out. A preliminary combustion test was carried out at 10 bar and the combustion chamber pressure was measured to be significantly lower than the target pressure. This is because it was a low pressure test, and it is expected to be resolved in the high pressure test in the future.