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RISS 인기검색어
- 검색키워드
- 저자 : A.R. Masri (검색결과 5 건)
- 무료
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PLIF 및 자발광 계측을 이용한 이중선회 가스터빈 연소기에서 연소불안정 모드 연구
Choi, Inchan,Lee, Keeman,Juddoo, Mrinal,Masri, A.R. 한국연소학회 2014 한국연소학회지 Vol.19 No.1
This paper described an experimental investigations of combustion instability mode in a lean premixed dual swirl combustor for micro-gasturbine system. When such the instability occurs, a strong coupling between pressure oscillations and unsteady heat release excites a self-sustained acoustic wave which results in a loud, annoyed sound and may also lead a structural damage to the combustion chamber. The detailed period of flame behavior and heat release in combustion instability mode have been examined with high speed OH and CH-PLIF system and $CH^*$ chemiluminescence measurement, flame tomography with operated at 10 kHz and 6 kHz each. Experiment results suggest that unstable flame behavior has a specific frequency with 200 Hz and this frequency is accords with about 1/2 sub-harmonic of combustor resonance frequency, not fundamental frequency. This is very interesting phenomenon that have not reported yet from other previous works. Therefore, when a thermo-acoustic instability with Rayleigh criterion occurs, the fact that the period of heat release and flame behavior are different each other was proposed for the first time through this work.
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이중 선회 가스터빈 연소기에서 연소 불안정 주기에 관한 실험적 연구
최인찬(Inchan Choi),이기만(Keeman Lee),A.R. Masri 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.12
본 연구는 이중선회 가스터빈 희박연소기에서 연소 불안정성에 대한 실험적인 연구이다. 연소기의 큰 손상 및 소음을 야기 시키는 연소기내에서 연소 불안정 발생은 압력파와 열방출 간의 상호작용에 의하여 유발되는 것으로 알려져 있다. 연소 불안정 현상을 규명하기 위하여 당량비 변화에 따른 CH 및 OH-PLIF (10kHz)를 통해 열 방출에 대한 정보를 얻었으며, 연소실의 음향파를 측정하여 연소실에서 압력변화에 대해 파악했다. 그 결과 불안정한 화염영역에서 화염 거동이 200Hz의 일정한 주기를 가지고 있음을 확인하였으며, 그 주기는 연소실의 길이에 의존되는 연소실 공명 주파수의 1/2 subhamonic 주기와 일치하는 것을 확인하였다. This parer described experimental investigations of the unsteady in a lean premixed dual swirl gas turbine combustor. Strong coupling between pressure oscillations and unsteady heat release excites a self-sustained acoustic wave which results in a loud, annoyed sound and may also lead to a structural damage to the combustion chamber. Heat release period in region of combustion instability has been examined with OH and CH-PLIF system, flame tomography and PLIF operated at 10kHz. Experiment results suggest that unstable flame behavior has a specific frequency with 200Hz and this frequency is accords with 1/2 subhamonic of resonance frequency.
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Kim, Jaehyeon,Jang, Munseok,Lee, Keeman,Masri, A.R. Elsevier 2019 Experimental thermal and fluid science Vol.105 No.-
<P><B>Abstract</B></P> <P>The main objective of this work was to investigate the beating behavior of acoustically self-excited instabilities in dual swirl combustors. This was achieved by measuring fluctuations in sound pressure and heat release, and analyzing the resulting frequency maps to evaluate the propensity for thermoacoustic instability. The experiments were carried out while varying the combustor length and thermal power. Consequently, the frequency map representing the sound pressure of the flame instability can be divided into two modes exhibiting different behaviors. According to the resonance frequency equation, the frequency of the thermoacoustic instability increases with the thermal power and decreases with the combustor length. In the case of Mode 1, when the thermal power is relatively high, the propensity for predominant frequencies is consistent with the trend indicated by the resonance equation. In Mode 2, on the other hand, when the thermal power is low, the frequencies remain nearly constant even when the combustor length increases. In the case of lower thermal power and longer combustor lengths, a new wave pattern is observed, in which two signals of similar cycles merge to generate a new signal. Under these conditions, the combustion intensity is approximately 2.0–3.0 MW/m<SUP>3</SUP> atm and the gradient of the combustion intensity decreases. This is caused by a beating phenomenon, which we verified by inputting the experimental results into the beating equation. We also analyzed high-speed images and measured the heat release fluctuations in the pilot flame, and confirmed that the pilot flame and main flame have different cycles, thus leading to beating.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A flame behavior of instability in dual swirl combustors is observed. </LI> <LI> The frequency of acoustic instability is divided into two modes. </LI> <LI> In the case of Mode 2 and longer combustor length, a new wave pattern is observed. </LI> <LI> The non-uniform wavelength occurs in the specific combustion intensity. </LI> <LI> Beating behavior occurs due to the different fluctuation cycles of flame. </LI> </UL> </P>
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PLIF를 이용한 이중 선회 가스터빈 연소기의 과도 및 불안정 모드 연구
최인찬(Inchan Choi),이기만(Keeman Lee),A.R. Masri 한국연소학회 2013 KOSCOSYMPOSIUM논문집 Vol.2013 No.12
This paper described experimental investigations of the transition and instability mode in a lean premixed dual swirl combustor. Strong coupling between pressure oscillations and unsteady heat release excites a self-sustained acoustic wave which results in a loud, annoyed sound and may also lead to a structural damage to the combustion chamber. Heat release analysis in instability and transition mode has been examined with OH and CH-PLIF system. flame tomography with operated at 10kHz. Experiment results suggest that unstable flame behavior has a specific frequency with 200Hz and this frequency is accords with 1/2 subhamonic of resonance frequency, not fundamental frequency. Also, it is confirmed that the combustion instability is strongly related to the CIVB phenomenon.
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PLIF 및 자발광 계측을 이용한 이중선회 가스터빈 연소기에서 연소불안정 모드 연구
최인찬(Inchan Choi),이기만(Keeman Lee),Mrinal Juddoo,A.R. Masri 한국연소학회 2014 한국연소학회지 Vol.19 No.1
This paper described an experimental investigations of combustion instability mode in a lean premixed dual swirl combustor for micro-gasturbine system. When such the instability occurs, a strong coupling between pressure oscillations and unsteady heat release excites a self-sustained acoustic wave which results in a loud, annoyed sound and may also lead a structural damage to the combustion chamber. The detailed period of flame behavior and heat release in combustion instability mode have been examined with high speed OH and CH-PLIF system and CH<SUP>*</SUP> chemiluminescence measurement, flame tomography with operated at 10 ㎑ and 6 ㎑ each. Experiment results suggest that unstable flame behavior has a specific frequency with 200 ㎐ and this frequency is accords with about 1/2 sub-harmonic of combustor resonance frequency, not fundamental frequency. This is very interesting phenomenon that have not reported yet from other previous works. Therefore, when a thermo-acoustic instability with Rayleigh criterion occurs, the fact that the period of heat release and flame behavior are different each other was proposed for the first time through this work.
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