• Title/Summary/Keyword: Combustion enhancement

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A Study on Combustion Characteristics of Methane Fuel according to Torch Nozzle Diameter in a Constant Volume Combustion Chamber (정적연소기에서 토치의 노즐 직경에 따른 메탄의 연소특성 파악)

  • Lee, Jung-Man;Kwon, Soon-Tae;Park, Chan-Jun;Ohm, In-Young
    • Journal of the Korean Society of Visualization
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    • v.8 no.1
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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.

A Study on Combustion Characteristic Methane Fuel according to Torch Volume Variation in a Constant Volume Combustion Chamber (정적연소기에서 토치의 체적 변화에 따른 메탄의 연소특성 파악)

  • Kwon, Soon-Tae;Park, Chan-Jun;Ohm, In-Young
    • Journal of the Korean Society of Visualization
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    • v.9 no.1
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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.

Development of High-Pressure Subscale Thrust Chamber for Verifying Core Technology for KSLV-II Performance Enhancement (한국형발사체 성능 고도화 핵심기술 검증을 위한 고압 축소형 연소기 개발)

  • Kim, Jonggyu;Kim, Seong-Ku;Joh, Miok;Ryu, Chulsung
    • Journal of the Korean Society of Propulsion Engineers
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    • v.25 no.4
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    • pp.19-27
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    • 2021
  • In this study, a high-pressure subsacle thrust chamber was developed to verify the core technology for KSLV-II performance enhancement. The core technologies are the design of an injector for high-pressure combustion, development of a combustion stabilization device using the additive manufacturing technique, and the design and fabrication of mixing head and regeneratively cooled combustion chamber. The core technologies, which have been verified through the development of high-pressure subscale thrust chamber, will be used to develop large engine liquid rocket engine thrust chamber in the future.

PROPAGATION PROCESSES OF NEWLY DEVELOPED PLASMA JET IGNITER

  • Ogawa, Masaya;Sasaki, Hisatoshi;Yosgida, Koji;Shoji, Hideo;Tanaka, Hidenori
    • International Journal of Automotive Technology
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    • v.3 no.1
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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.

Effect of the Configuration of Plasma Jet Plug on Combustion Characteristics in a Constant Volume Vessel (플라즈마 제트 플러그의 형상이 정적연소기내 연소특성에 미치는 영향)

  • Kim, Munheon;Yoo, Hoseon;Oh, Byungjin;Park, Jungseo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.5
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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.

Combustion Characteristics of Orifice Size of Torch in a CVCC (토치 점화 장치의 오리피스 직경에 따른 연소특성 파악)

  • Kwon, Soon-Tae;Kim, Hyeong-Sig;Choi, Chang-Hyeon;Park, Chan-Jun;Ohm, In-Young
    • 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.

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Evaluation of Heat Loss by Means of Plasma Jet Ignition during Combustion Duration in the Constant Volume Vessel (정적연소실내에서의 플라즈마 제트 점화에 대한 연소기간중의 열손실산정)

  • 김문헌;문경태;박정서;김홍성
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.2
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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.

Numerical Investigation on the Thermal Characteristics of Mild Combustion According to Co-axial Air (동축공기에 따른 Mild 연소의 열적 특성에 대한 수치연구)

  • Hwang, Chang-Hwan;Baek, Seung-Wook;Kim, Hak-Young
    • Journal of the Korean Society of Combustion
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    • v.15 no.4
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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.

Effects of Ball Milling for Elemental Powders on Ni-Al based Intermetallics Coating on Mild Steel through Induction Heating Process (Ni-Al계 금속간화합물의 고주파 연소합성코팅에 미치는 볼 밀링의 영향)

  • Lee, Han-Young;Park, Won-Kyu
    • Tribology and Lubricants
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    • v.33 no.6
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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.

Study on the Enhancement of Design Technology for the Evaporation Pot Type Kerosene Burner (기화식 석유버너의 설계기술 향상 연구)

  • Shim, S.H.;Kim, S.J.;Keel, S.I.;Hong, Y.J.;Yun, J.H.;Kim, I.K.;Kim, Y.S.
    • 한국연소학회:학술대회논문집
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    • 1998.10a
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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.

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