• 제목/요약/키워드: Combustion oscillation

검색결과 160건 처리시간 0.031초

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

  • 양영준
    • Journal of Advanced Marine Engineering and Technology
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    • 제28권7호
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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.

표면연소기의 저주파 연소진동음의 특성 (Characteristics of Low-Frequency Combustion-driven Oscillation in a Surface Burner)

  • 한희갑;이근희;권영필
    • 소음진동
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    • 제10권6호
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    • pp.991-997
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    • 2000
  • The objective of this study is to examine the onset condition and the frequency characteristics of the low-frequency combustion oscillation in a surface burner. For this purpose, extensive parametric studies have been performed experimentally and the effects of size of each section, the equivalence ratio, and the entrance velocity on oscillatory behavior explored. The experimental results were discussed in comparison with the other combustors associated tilth the low-frequency combustion oscillation. The combustion mode is driven at high combustion rate by the lift of unstable flame near the lower limit of the combustible equivalence ratio. The oscillation frequency is dependent not on the burner geometry but on the equivalence ratio and the combustion load. Low-frequency combustion mode was formed to be divided into two different modes, named C1 and C2 respectively. Two modes occurred individually, simultaneously or transitionally according to the equivalence ratio and combustion load. The characteristics of low-frequency oscillation is different from each other depending on the type of combustors. The surface burner has also its own characteristics of low -frequency oscillation.

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Symptoms of Self-excited Combustion Oscillation and their Detection

  • Yang, Young-Joon;Akamatsu, Fumiteru;Katsuki, Masashi;Bae, Suk-Tae;Kim, Si-Pom
    • Journal of Mechanical Science and Technology
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    • 제18권10호
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    • pp.1859-1868
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    • 2004
  • Monitoring of OH chemiluminescence through an optical fiber was demonstrated to be a useful method in detecting self-excited combustion oscillations. OH chemiluminescence intensity detected by the optical fiber showed mostly excellent agreement with those obtained by high speed CCD camera measurements when combustion oscillations were strong. 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, we have found and proposed unique measures to tell 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.

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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    • 제17권11호
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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.

Silo 형 가스터빈 연소기에서 발생하는 연소진동 분석 및 저감 (Analysis of Combustion Oscillation and its Suppression in a Silo Type Gas Turbine Combustor)

  • 서석빈;안달홍;차동진;박종호
    • 설비공학논문집
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    • 제21권2호
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    • pp.126-130
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    • 2009
  • The present study describes an investigation into the characteristics of combustion oscillation and its suppression instability of a silo type gas turbine combustor in commercial power plant. Combustion oscillation is occurred the combustor in near full load during operation. As a result of FFT analysis of the combustion dynamics, the frequency of the oscillation is analyzed as the 1'st longitudinal mode of acoustic resonance of the combustor. For suppress of the instability, combustion tuning with adjust of fuel valve schedule is carried out, which changes equivalent ratio of each burners. As the result, the oscillation is successfully reduced with meeting the level of NOx emission regulation.

가스히터의 소음 진동 원인 분석 (A cause analysis of Noise & Vibration of Gas Heater)

  • 고재필;유현석
    • 한국가스학회지
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    • 제13권1호
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    • pp.9-13
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    • 2009
  • 가스히터의 가동으로 인하여 발생하는 소음 및 진동의 주 원인은 연소음(combustion roar)과 연소진동음(combustion oscillation)이다. 연소음(combustion roar)의 특징은 음압이 넓은 주파수대에 걸쳐 있고, 크기도 비교적 일정 하다. 반면 연소진동음(combustion oscillation)은 연소실내 기체의 고유진동수에 대하여 버너계가 Positive Feedback을 일으켜 공진할 때 발생되는 소음 및 진동이다. 따라서 소음 및 진동을 해결 할 수 있는 방법은, 공진을 피하는 것이다. 첫 번째, 버너에서 연료와 공기량의 비율을 조절하여 진동수를 변화시키거나, 연소실내에서의 연료와 공기의 혼합속도를 변화시키는 방법이 있다. 두 번째, 연소실의 길이나 이코노마이저(Economizer)의 형상을 바꾸어 고유진동수를 변경시키는 방법이 있다. 본 논문에서는 이코노마이저(Economizer)를 변경하여 공명을 회피하였다.

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발전용 가스터빈에서 발생하는 연소진동 특성 및 이상연소진동의 저감 (Characterization of Combustion Oscillation and Reduction of Abnormal Oscillation in a Power Generation Gas Turbine)

  • 서석빈;안달홍;정재화
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.1682-1685
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    • 2004
  • Gas Turbine combustors for power plant can be reduced NOx emissions using lean premixed combustion technology. But the combustors are likely to occur combustion oscillations which damage operation reliability and mechanical life of the gas turbines. In this paper, characterizations of oscillation in a gas turbine combustor for power plant are presented. Combustion dynamics occur $1{\sim}1.5$ psi in amplitude with low frequency less than 140Hz during normal operation. An abnormal high level dynamics, 2.0 psi amplitude occur at 125 Hz frequency. Abnormal combustion oscillation is reduced by modulation of fuel supply valve control schedule.

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수치해석을 이용한 맥동연소과정 및 NOx 배출특성 해석 (Numerical Simulations for Combustion and NOx Emission Characteristics in Oscillating Combustion Burner)

  • 김후중;조한창
    • 한국연소학회지
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    • 제14권3호
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    • pp.37-44
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    • 2009
  • An experimental study was conducted to reduce NOx emission in RT(radiant tube)burner by using oscillating combustion processes in RIST. A solenoid valve gives the various oscillating conditions, such as oscillation frequency, duty ratio of fuel flow. In this study, we used commercial software, CFD-ACE+ to predict combustion and NOx emission characteristics for various experimental oscillation conditions. The effect of oscillation frequency and duty ratio on NOx emission will be discussed in terms of flow field, temperature and equivalence ratio distributions in detail.

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Characteristics of Unsteady Combustion and Combustion Control by Pulsating Mixture Supply

  • Yang, Young-Joon;Akamatsu, Fumiteru;Katsuki, Masashi
    • 한국연소학회지
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    • 제6권2호
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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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