• 한국안전학회지
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• 제7권3호
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• pp.3-13
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• 1992

In recent years, the study about the high efficiency and low fuel consumption of the internal conbustion engine has been mainly proceeding. To achieve these goals, the improvement of combustion process in Sl engine and the use of substitute energy are suggested. When the methanol blend fuel Is used, the combustion rate of the initial ignition is diminishing by high latent evaporation of methanol. But it attracts the attention because of the high octane number, and lean mixture peculiarity. Considering these facts, the gasoline-methanol blend fuel In engine operation has been used to compare and analyze the pressure development, rate of heat release, mass burned fraction, and combustion process. The results of experiment show the power increase, lean combustion and low harmful component of emission.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.301-303
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• 2014

Flameless combustion, well known as MILD (Moderate Intensity Low oxygen Dilution) combustion or CDC(Colorless Distributed Combustion), is considered as one of the promising technology for achieving low NOx and CO emissions with improving thermal efficiency of combustion system. In this paper, the effects of exhaust gas dilution rate on formation of flameless combustion of liquid fuel were analyzed using three-dimensional numerical simulations for application of gas turbine combustor with high power density. Results show that the local high temperature region was decreased and flame temperature was spatially uniformly distributed due to higher dilution rate of burnt gas as similar pattern of gas phase flameless combustion. But the evaporation and mixing process of liquid fuel are found to be another important factors for formation of flameless combustion.

• 한국항공우주학회지
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• 제46권7호
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• pp.567-574
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• 2018

스월은 연료의 후퇴율 증가뿐 아니라 연소 압력의 진동을 감소시키며, 하이브리드 로켓의 연소안정화에 기여하는 것으로 알려져 있다. 따라서 스월 산화제 분사에 의한 주연소실 내부의 유동 구조의 변화를 이해하고 연소안정화의 물리적 과정을 실험적으로 연구하였다. 결과에 의하면, 스월은 주연소실의 유동 구조를 변화시켜 후연소실의 500Hz 대역 p'과 q'의 발생을 억제할 뿐 아니라 두 진동의 위상차를 변화하여 상호결합(coupling)에 영향을 주고 있음을 확인했다. 또한 후연소실 화염 가시화를 통하여 스월에 의한 선회운동량의 증가로 와류발생과 흘림 등이 변화하여 연소안정화에 기여하는 것으로 분석됐다.

• 한국자동차공학회논문집
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• 제4권2호
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• pp.11-22
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• 1996

It has been generally accepted that NOx formation increases as the maximum temperature or correspondingly the maximum pressure of a combustion system increases. Recently some exceptional experimental results have been reportes that under certain circumstance NOx formation could be reduced while the maximum pressure was increasing by varying the methods of combustion for the same kind of premixed gases. Until now that kind of results have been acquired only for the case of a dual opposed prechamber. But the mechanism has not been clearly understood yet. 3D computer simulation has been tried to clarify the mechanism. Flor this purpose KIVA-Ⅱ has been modified and applied to the model combustion chamber with which the same kind of experimental works have been done by the authors. A good agreement with the experimental results was achieved with the spatial and temporal resolution which is hard th be obtained by the experimental methods. And it was observed that for the dual opposed prechamber case the time for the NOx formation, which is non-equilibrium reaction, is shorter than any other case by an appropriate mixing process in the main combustion chamber. The shorter time reduceed heat loss through the combustion chamber walls and thereby obtaines the higher maximum pressure.

• 한국연소학회지
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• 제20권3호
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• pp.13-20
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• 2015

The performance of a direct-injection diesel engine often depends on the strength of swirl or squish, the shape of combustion chamber, the number of nozzle holes, etc. This is natural because the combustion in the cylinder was affected by the mixture formation process. Since the available duration to make the mixture formation of air-fuel is very short, it is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this paper, the combustion process of a common-rail diesel engine was studied by employing two kinds of pistons. One has several cavities on the piston crown to intensify the squish during the compression stroke in order to improve the atomization of fuel, we call this multi cavity piston in this paper. The other is a toroidal single cavity piston, generally used in high speed diesel engines. To take photographs of flame and flaming duration, a four-stroke diesel engine was remodeled into a two-stroke visible single cylinder engine and a high speed video camera was used.

• 대한기계학회논문집
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• 제16권11호
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• pp.2159-2168
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• 1992

본 연구에서는 CWS 액적의 가열 및 연소에 관한 현상규명에 있어서 액적크기, CWS 석탄함량 및 연소분위기 가스온도, CWS 액적중의 미분된 석탄입자의 크기와 특히 분위기중의 산소농도의 변화에 의한 영향을 파악하고자 한다.

• 대한기계학회논문집
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• 제16권9호
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• pp.1744-1759
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• 1992

본 연구에서는 conchas-spray 코드를 근간으로 하여 기관 실린더 내의 난류유 동과 난류연소 현상을 경제적이고 정확하게 해석할 수 있는 다차원 수치해석 프로그램 을 개발하므로, 전기점화 기관의 흡입, 압축, 연소 과정에 대한 수치해석의 가능성을 제시하고, 스월수 0.0, 0.6, 1.2와 2.4의 파라미터 연구를 통하여 스월이 난류유동 및 난류연소에 미치는 영향을 파악하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 추계 학술대회논문집
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• pp.18-21
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• 2006

This paper investigates LES of turbulent combustion flow based on 2-scalar flamelet approach, where a G-equation and a conserved scalar equation simulate a propagation of premixed flame and a diffusion combustion process, respectively. The turbulent SGS modeling on these flamelet combustion approach is also researched. These LES models are applied to an industrial flows in a full scale gasturbine combustor with premixed and non-premixed flames. The numerical results predict the characteristics of experiment temperature profiles. Unsteady features of complex flames in combustor are also visualized.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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• pp.77-78
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• 2012

To predict combustion instability in actual full-scale combustion chamber of rocket engines, air-injection test is proposed with scaling techniques. From the data, damping factors have been obtained as a function of hydraulic parameter and the data give us instability map. Two instability regions are presented and it is found that they coincide reasonably with them from hot-fire test with full-scale flow rates. Accordingly, the proposed approach can be applied cost-effectively to stability rating of jet injectors when mixing of fuel and oxidizer jets is the dominant process in instability triggering.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제21회 KOSCO SYMPOSIUM 논문집
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• pp.3-8
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• 2000