• 한국가시화정보학회지
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• 제8권1호
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• pp.19-24
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• 2010

Five 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 burned fraction and combustion enhancement rate. The combustion pressures were measured to calculate the mass burned fractions 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.

• 한국가시화정보학회지
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• 제9권1호
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• pp.42-48
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• 2011

Six different size of torch-ignition device were applied in a constant volume combustion chamber for evaluating the effects of torch-ignition on combustion. The torch-ignition device was designed for six different volumes and same orifice size. The combustion pressures were measured to calculate the mass burn fraction and combustion enhancement rate. In addition, the flame propagations were visualized by shadowgraph method for the qualitative comparison. The result showed that the combustion pressure and mass burn fraction were increased when using the torch ignition device. And the combustion duration were decreased. 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. Finally, the initial flame propagation was affected by torch-ignition volume.

• 한국추진공학회지
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• 제25권4호
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• pp.19-27
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• 2021

한국형발사체용 연소기 성능 고도화를 위한 핵심기술을 검증하기 위해 고압 축소형 연소기를 개발하였다. 성능 고도화를 위한 핵심기술은 고압 연소기용 분사기 설계, 적층제조기법을 적용한 연소안정화 장치 개발, 고압 축소형 연소기 헤드 및 재생냉각 연소실 설계/제작 등이다. 고압 축소형 연소기 개발을 통해 핵심기술을 검증하였고, 이 기술들은 향후 대형 액체로켓엔진 연소기 개발에 활용될 예정이다.

• International Journal of Automotive Technology
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• 제3권1호
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• pp.9-16
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• 2002

In plasma jet ignition, combustion enhancement effects occur toward the plasma jet issuing direction. Therefore, when the igniter is attached at the center of a cylindrically shaped combustion chamber, plasma jet should issue toward the round combustion chamber wall. The plasma jet igniter that had an annular circular orifice has been developed. The purpose of this study is to elucidate the relationship between the newly developed plasma Jet igniter configuration and combustion enhancement effects. In this newly developed plasma Jet igniter, flame front wrinkle appears on the flame front and flame propagates rapidly. Plasma Jet influences on the flame propagation far long period when the plasma jet igniter has issuing angle 90 degrees and large cavity volume, because the plasma jet only lasts several ms. However, in the early stage of combustion, flame front area of issuing angle 45 degrees is larger than that of 90 degrees, because the initial flame kernel is formed by the plasma jet.

• 대한기계학회논문집B
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• 제23권5호
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• pp.593-602
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• 1999

This paper presents combustion characteristics of LPG-air mixture ignited by the plasma jet in a cylindrical vessel with constant volume, in which our focus is placed on the multi-hole plug configuration. Four types of the plug configuration depending on the number of orifice and the arranged angle are considered, along with two cases of conventional spark ignition for comparison. Not only the flame propagation is photographed at intervals, but the pressure in the combustion chamber is also recorded through the entire combustion process. The results show that the plasma jet ignition enhances the overall combustion rate remarkably in comparison to the spark ignition by generating irregular flame front and penetrating through the unburned mixture. The combustion enhancement rate agrees favorably with the available data, which supports the validity of our experiment. Synthetically estimating, the two-hole sixty-degree plug appears to be the most desirable, in that the maximum pressure as well as the combustion duration is less affected by the sub-energy level than the others. It is also deduced that there may exist an optimal plug configuration capable of rapid combustion for a specific combustion chamber.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2010년도 춘계학술 발표회
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• pp.59-63
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• 2010

토치 점화 장치의 연소 특성을 파악하기 위하여 7개의 각기 다른 토치 점화 장치를 설계하였다. 토치 점화장치의 오리피스 직경에 따른 특성을 파악하기 위하여, 토치 점화 장치의 체적과 높이는 고정하고, 오리피스 직경을 4mm에서 16mm까지 2mm씩 증가시키며 실험하였다. 초기 화염 생성 및 전파는 질량 연소율과 연소 촉진율로 분석하였다. 질량 연소율과 연소 촉진율을 계산하기 위하여 정적 연소실 내의 평균 압력을 측정하였다. 또한 shadow graph법을 이용하여, 초기 화염 생성과 화염 전파과정 전 영역을 가시화하였다. 토치 점화 장치를 사용한 경우에는 일반적인 스파크 점화와 비교하여 질량 연소율의 기울기가 증가하였고, 연소 촉진율도 개선된것을 확인하였다. 또한 가시화된 이미지를 확인한 결과 토치 점화 장치를 사용하면 초기 화염 발달 단계에서 화염이 난류 화염으로 천이되어 연소가 촉진된것을 확인하였다.

• 한국자동차공학회논문집
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• 제11권2호
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• pp.96-103
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• 2003

In this paper, the heat loss to the constant volume vessel wall was investigated using instantaneous heat flux sensor, schlieren visualization, pressure rise curve. And the heat loss characteristics of plasma jet ignition were compared with conventional spark ignition. In case of plasma jet ignition, the flame kernel moves toward the center of combustion vessel in the initial period of combustion, and the flame surface spread out to the vessel wall. However, in case of conventional spark ignition, the flame surface contact with combustion vessel wall in the initial period of combustion. As a result, heat loss in the combustion duration for conventional spark ignition increase faster than that of plasma jet ignition. And the combustion enhancement rate of plasma jet ignition is higher than that of conventional spark ignition, and it was found that the heat loss rate is inversely proportional to the combustion enhancement rate.

• 한국연소학회지
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• 제15권4호
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• pp.1-8
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• 2010

Mild combustion is considered as a promising combustion technology for energy saving and low emission of combustion product gases. In this paper, the controllability of reaction region in mild combustion is examined by using co-axial air nozzle. For this purpose, numerical approach is carried out. Propane is considered for fuel and air is considered for oxidizer and the temperature of air is assumed 900K slightly higher than auto ignition temperature of propane. But unlike main air, the atmospheric condition of co-axial air is considered. Various cases are conducted to verify the characteristics of Co-Axial air burner configuration. The use of coaxial air can affect reaction region. These modification help the mixing between fuel and oxidizer. Then, reaction region is reduced compare to normal burner configuration. The enhancement of main air momentum also affects on temperature uniformity and reaction region. The eddy dissipation concept turbulence/chemistry interaction model is used with two step of global chemical reaction model.

• Tribology and Lubricants
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• 제33권6호
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• pp.296-302
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• 2017

Ball milling of elemental powders in advance and using an induction heating system for intermetallic coatings are known to enhance the reactivity of combustion synthesis. In this work, the effects of simultaneously applying these two incentive methods on the properties of intermetallic coatings are studied. Ni-Al powder compacts ball-milled with three different ball-to-powder weight ratio mixtures are synthesized and coated on mild steel by combustion synthesis in an induction heating system. Consequently, similar to an electrical heating system, the positive effects of ball milling on the combustion synthesis are confirmed in the induction heating system. The enhancement in synthetic reactivity achieved by applying the two incentive methods at the same time is greater than that by applying each incentive method separately. In particular, the enhancement is remarkable at low reaction temperature. However, there are limitations to improving the reactivity by simultaneously applying the two incentive methods to the combustion synthesis, unlike the reaction temperature. The microstructure and hardness of the coating layer are both influenced by the ball-charging ratio employed in the ball-milling process.

• 한국연소학회:학술대회논문집
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• 한국연소학회 1998년도 제17회 KOSCI SYMPOSIUM 논문집
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• pp.47-57
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• 1998

Characteristics of evaporation, flame propagation at moment of ignition and steady state combustion, and flow characteristics of combustible mixture have been investigated by experiments and computational simulation for the evaporation pot type kerosene burner. The results show how to design the evaporation pot in order to minimize the sticking of residual tar, and also indicate that symmetrical flame propagation along the flame ring from the kernel of ignition is achieved by modication of the shape of ignition part. In the case of steady state combustion, the uniform distribustion of flame at each flame hole is accomplished by proper modification of the piping instruments. The improved design of the structure and parts of the kerosene burner make up enhancement of flame stability and considerable reduction of CO and bad smell emission at moment of ignition.