• Title, Summary, Keyword: combustion

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Status and perspectives of the advanced catalytic combustion (촉매연소의 신기술 동향)

  • Kang, Sung-Kyu
    • 한국연소학회:학술대회논문집
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    • pp.299-308
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    • 2003
  • This paper provides a review of the status and of the perspectives of advanced catalytic combustion for ultra clean combustion of gas turbines and for industrial combustors. The development of catalytic materials and their combustion techniques for gas turbines are briefly reported. The fuel-rich approaches to catalytic combustion are mentioned for a new technology of thermal- and fuel-NOx control. The fuel-rich catalytic combustion are also applicable to the combustor of ceramic gas turbine, and to the combustion of biomess and municipal waste sludge. Some extended technologies of combustion synthesis are introduced for the synthesis of carbon nanotube and of Perovskite combustion catalysts

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Combustion Control and Symptom Detection on Self-excited Combustion Oscillation (자려 연소진동에 관한 연소제어와 징후의 검출)

  • Yang Young-Joon
    • Journal of the Korean Society of Marine Engineering
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    • v.28 no.7
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    • pp.1111-1122
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    • 2004
  • An idea to suppress the self-excited combustion oscillation was applied to the flames. The characteristics of unsteady combustion were examined and the unsteady combustion was driven by forced pulsating mixture supply that can modulate its amplitude and frequency. The self-excited combustion oscillation having weaker flow velocity fluctuation intensity than that of the forced pulsating supply can be suppressed by this method. The effects of the forced pulsation amplitude and frequency on controlling self-excited combustion oscillations were also investigated comparing with the steady mixture supply. The unsteady combustion used in this experiment plays an important role in controlling self-excited combustion oscillation. Symptoms of self-excited combustion oscillation were also studied in order to predict the onset of combustion oscillation before it proceeded to a catastrophic failure For the purpose, the unique measures to observe the onset of self-excited combustion oscillations based on the careful statistics of fluctuating properties in flames, such as pressure or emission of OH radicals, have been proposed.

Characteristics of High-Frequency Combustion Instabilities Occurring in Combustion Devices (연소장치에서 발생하는 고주파 연소 불안정 특성)

  • Seo, Seong-Hyeon
    • Journal of the Korean Society of Combustion
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    • v.17 no.1
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    • pp.30-36
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    • 2012
  • Dynamic characteristics of combustion occurring in various combustion devices have been extensively studied since most of high-performance combustion devices are susceptible to hazardous, unstable combustion that deteriorates combustor's lifetime. One of the most severe unstable combustion phenomena is high-frequency combustion instability in which heat release fluctuations from combustion are coupled to resonant modes of the combustor. Here in this study, characteristics of high-frequency combustion instabilities observed in three different combustion devices have been presented. Lean-premixed combustion instability occurs mainly due to equivalence ratio fluctuations which induce large heat release oscillations at lean conditions. Liquid-fueled combustion also shows high-frequency instability from energy coupling between pressure and heat release oscillations.

Understanding and Application of MILD combustion (마일드연소의 이해와 응용)

  • Kim, Nam Il
    • 한국연소학회:학술대회논문집
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    • pp.281-282
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    • 2014
  • Recently, studies on Mild combustion have grown in many combustion application fields in the international combustion society. Compared with international activities in this field, domestic study in Korea has not been activated yet. This brief review aims to explain some essences of fundamental physics of Mild combustion and to introduce some recent application techniques of them. Fundamental physics of Mild combustion has been usually broken down into three aspects [1]; physical, thermodynamic, and chemical aspects. A major portion of Mild combustion physics is related to HiTAC (High Temperature Air Combustion) or HiCOT (High Temperature Combustion Technology). Although definition of Mild combustion is easily accepted among combustion engineers, combustion control in Mild combustion may be difficult without understanding essential physics of it. To encourage the research in this field, some representative cases will be introduced, and related essential techniques will be explained.

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Characteristics of Unsteady Combustion and Combustion Control by Pulsating Mixture Supply

  • Yang, Young-Joon;Akamatsu, Fumiteru;Katsuki, Masashi
    • Journal of the Korean Society of Combustion
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    • v.6 no.2
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    • pp.8-14
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    • 2001
  • The effects of unsteady combustion are experimentally studied using forced pulsating mixture supply. It was shown that unsteady combustion used in this experiment plays an important role in controlling self-excited combustion oscillations. It may also have desirable performances, from a practical point of view, such as high combustion load, augmented heat transfer, reduced pollutant emissions and so on. We examined the characteristics of unsteady combustion driven by forced pulsating mixture supply in a small duct-combustor with a rearward-facing step. Further, we found its influence on the onset of self-excited combustion oscillations, the possibility of suppressing self-excited combustion oscillations and the reason why the self-excited combustion oscillation was suppressed using the forced pulsating mixture supply, comparing with the steady mixture supply.

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Characteristics of Self-excited Combustion Oscillation and Combustion Control by Forced Pulsating Mixture Supply

  • Yang, Young-Joon;Fumiteru Akamatsu;Masashi Katsuki;Lee, Chi-Woo
    • Journal of Mechanical Science and Technology
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    • v.17 no.11
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    • pp.1820-1831
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    • 2003
  • Characteristics of self-excited combustion oscillation are experimentally studied using confined premixed flames stabilized by a rearward-facing step. A new idea to suppress combustion oscillation was applied to the flames. The characteristics of unsteady combustion were examined, which is driven by forced pulsating mixture supply that can modulate its amplitude and frequency. The self-excited combustion oscillation having weaker flow velocity fluctuation intensity than that of the forced pulsating supply can be suppressed by the method. The effects of the forced pulsation amplitude and frequency on controlling self-excited combustion oscillations were also investigated comparing with the steady mixture supply. The unsteady combustion used in this experiment plays an important role in controlling self-excited combustion oscillations, and it also exhibits desirable performances, from a practical point of view, such as high combustion load and reduced pollutant emissions of nitric oxide.

A Study on the Combustion Characteristics according to Evaporation rate of Methanol - Blended Fuel (메탄올 혼합 연료의 기화율 변화에 따른 연소특성에 관한 실험적 연구)

  • Cho, H.M.
    • Journal of ILASS-Korea
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    • v.2 no.2
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    • pp.24-34
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    • 1997
  • This paper describes the investigation of combustion characteristics of gasoline-methanol blend in constant volume combustion chamber. A constant volume combustion chamber was used to elucidate a basic combustion characteristics and the premixer was installed to control temperature and equivalence ratio. And the maximum pressure, combustion duration and flame propagation according to the evaporation rate were measured to determine the optimal temperature range for evaporating a blend fuel. These experimental results indicate that the combustion characteristics such as combustion chamber pressure and combustion were deteriorated by decreasing surrounding temperature of fuel. These experimental results indicate that the combustion characteristics such as combustion chamber pressure and combustion were deter orated by decreasing surrounding temperature of fuel injected. It was also found that the overall gasification process for methanol blend fuel was influenced by a combustion chamber temperature rather than a premixer temperature.

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NO Emission Characteristics of Oxygen-Enriched Combustion with $CO_2$ Recirculation in Counterflow Diffusion Flame (대향류 화염에서 $CO_2$ 재순환 산소부화연소의 NO 배출 특성)

  • Park, June-Sung;Cho, Han-Chang;Park, Jeong
    • Journal of the Korean Society of Combustion
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    • v.12 no.1
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    • pp.28-37
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    • 2007
  • Numerical study is conducted to grasp the flame structure and NO emissions for a wide range of oxy-fuel combustion (covering from air blown combustion to pure oxygen combustion) and for various mole fractions of recirculated $CO_2$ in $CH4-O_2/N_2/CO_2$ counterflow diffusion flames. Special concern is given to the difference of the flame structure and NO emissions between air blown combustion and oxy-fuel combustion w/o recirculated $CO_2$ and is also focused on chemical effects of recirculated $CO_2$. Air blown combustion and oxy-fuel combustion w/o recirculated $CO_2$ are shown to be considerably different in the flame structure and NO emissions. Modified fuel oxidation reaction pathways in oxygen-enriched combustion are provided in detail compared to those in air blown combustion w/o recirculated $CO_2$. The formation and destruction of NO through Fenimore and thermal mechanisms are also compared for air blown combustion and oxyegn-enriched combustion w/o recirculated $CO_2$, and the role of the recirculated $CO_2$ and its chemical effects are discussed. Importantly contributing reaction steps to the formation and destruction of NO are also estimated in oxygen-enriched combustion in comparison to air blown combustion.

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ANALYSIS OF DIRECT INJECTION SI STRATIFIED COMBUSTION IN HYDROGEN LEAN MIXTURE - COMBUSTION PROMOTION AND COOLING LOSS BY HYDROGEN -

  • Shudo, Toshio;Tsuga, Koichiro
    • International Journal of Automotive Technology
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    • v.2 no.3
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    • pp.85-91
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    • 2001
  • Characteristics of methane direct-injection spark-ignition stratified combustion in lean hydrogen mixture were analyzed both in a single cylinder engine and in a constant volume combustion chamber. Combustion pressure and Instantaneous combustion chamber wall temperature during the combustion process were measured with a thin-film thermocouple and used in analyses of combustion and cooling loss. Results in this research show that the premixed hydrogen increases cooling loss to combustion chamber wall while achieving combustion promotion, and the combustion system is effective especially in lean mixture conditions. Analysis of flame propagation was also done with Schlieren photography in the constant volume combustion chamber.

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Development of the Small Wastes Incinerator with High Combustion Efficiency (연소효율이 우수한 소형 소각로의 개발)

  • 한돈희;하대성
    • Journal of Environmental Health Sciences
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    • v.26 no.3
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    • pp.81-85
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    • 2000
  • In order to reduce emission of air pollutants from spot incineration, it is required to develope the combustion chamber of small wastes incinerator having combustion efficiency. The characteristics of combustion of the incinerator with combustion chamber having tangential angels with surface of 45$^{\circ}$of air supply nozzles were studied in accordance with non-grate, fixed-grate and shaking-grate in the combustion chamber. Combustion conditions were evaluated with combustion efficiency, emission of hazardous gases, temperatures, ignition loss of ash and so on. Combustion efficiencies were shown 73.9% for non-gate, 81.1% for fixed-grate and 89.0% for shaking-grate. Emissions of CO were revealed 6.52 ppm for non-grate, 273 ppm for fixed-grate and 224 for shaking-grate. Comprehensively evaluated, combustion conditions got better in order of shaking-grate, fixed-grate and non-grate. This study suggests that small wastes incinerator should have shaking-or fixed-grate in combustion chamber to get better combustion condition even though at expensive cost of manufacturing.

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