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RISS 인기검색어
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- 저자 : 허필원(Pilwon Heo) (검색결과 5 건)
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부상된 수소난류확산화염에서 동축공기의 음향가진에 의한 NOx 저감
허필원(Pilwon Heo),오정석(Jeongseog Oh),윤영빈(Youngbin Yoon) 한국연소학회 2008 KOSCOSYMPOSIUM논문집 Vol.- No.-
The effect of acoustic excitation to the emission level of NOx was investigated. The purpose of this work was to study the effects of acoustic excitation on NOx emission reduction and mixing of fuel and air. A compression driver was attached to the coaxial air supply tube to impose excitation. Acoustic excitation experiments at various frequencies were performed to find out the effective excitation frequency. Then schlieren photographs were taken to visualize the flow near the lifted flame base. Experimental results shows that excitation with the frequencies similar to the resonance frequencies of combustor could reduce NOx emission significantly. This reduction was influenced by fluctuation of coaxial air jet velocity at nozzle exit. The vortices formed by the coaxial air jet velocity fluctuation helped mixing of hydrogen and coaxial air, lowering NOx 'emission.
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GE 7FA+e DLN-2.6 가스터빈 연소기에서의 on-line 동압 측정 시스템
허필원(Pilwon Heo),오정석(Jeongseog Oh),윤영빈(Youngbin Yoon) 한국연소학회 2008 KOSCOSYMPOSIUM논문집 Vol.- No.-
Many of modem gas turbines use dry low NOx technology, which bums fuel in lean premixed condition, to reduce pollutant emission. However because of the susceptibility of combustion instability, it is very important to monitor the dynamic pressure of combustor. There are two types of pressure measuring probe commonly used: the long line probe and the cavity type probe. Knowing that it is more cost-effective to use long line probe, the on-line dynamic pressure monitoring system was composed in this research to build own measurement system. The frequency response of measuring probe was analyzed, and the simultaneous measurement with existing GE measuring toolkit was done to confirm the value in use.
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부상된 수소난류확산화염에서 동축공기의 음향가진에 의한 NOx 저감
허필원(Pilwon Heo),오정석(Jeongseog Oh),윤영빈(Youngbin Yoon) 한국연소학회 2009 한국연소학회지 Vol.14 No.1
The effects of acoustic excitation of coaxial air on mixing enhancement and reduction of nitrogen oxides (NOx) emission were investigated. A compression driver was attached to the coaxial air supply tube to impose excitation. Measurements of NOx emission with frequency sweeping were performed to observe the trend of NOx emission according to the fuel and air flow conditions and to inquire about the effective excitation frequency for reducing NOx. Then, Schlieren photographs were taken to visualize the flow field and to study the effect of excitation. In addition, phase-locked particle image velocimetry (PIV) was performed to acquire velocity field for each case and to investigate the effect of vortices more clearly. Direct photographs and OH chemiluminescence photographs were taken to study the variation of flame length and reaction zone. It was found that acoustic forcing frequencies close to the resonance frequencies of coaxial air supply tube could reduce NOx emission. This NOx reduction was influenced by mixing enhancement due to large-scale vortices formed by fluctuation of coaxial air jet velocity.
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오정석(Jeongseog Oh),허필원(Pilwon Heo),윤영빈(Youngbin Yoon) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5
The effects of acoustic excitation on the reduction in nitric oxidant (NOx) emission were experimentally investigated in non-premixed lifted hydrogen jet flames with coaxial air. The purpose of this work was to find an effective method to reduce NOx emission, to analyse the acoustic forcing effect on the flow field, the reaction zone, and NOx emission, and to study NOx reduction mechanisms. For the analysis of the flow field, a PIV method was used that incorporated two Nd-YAG lasers and a CCD camera. The reaction zone was visualized by taking OH<SUP>*</SUP> chemiluminescence images with a 307.1±5 ㎚ narrow band pass filter and an ICCD camera. A flow condition was carefully selected at uF=200 ㎧ and uA=16 ㎧, which was sustainable for the acoustic excitation in a lifted flame region. The frequency was swept from 150 to 1000 ㎐ in 5 ㎐ steps. And then NOx emissions were detected with a NOx sensor and recorded in a DAQ system. From the measurements of the flow field, the reaction zone, and NOx emission, we concluded that NOx emission was reduced and minimized at a resonance frequency. The vortex that was generated by acoustic forcing promoted air entrainment and enhanced fuel-air premixing. This premixing effect resulted in a lower flame temperature, and thus, a lower NOx emission.
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오정석(Jeongseog Oh),김민기(Minki Kim),허필원(Pilwon Heo),이장수(Jangsoo Lee),윤영빈(Youngbin Yoon) 한국추진공학회 2008 한국추진공학회지 Vol.12 No.5
Combustion vibration and yellow plume are frequently occurred during an initial operating mode in GE 7FA+e DLN-2.6 combustors which are running at Seo-Inchon combined cycle power plant. The objectives of this paper are to analyze the causes of those two phenomena and to study non-dimensional factors to design a lab scale dump combustor. With the consideration of real combustor, the peak frequencies of vibration is 120~140 Hz due to cold flow in plenum. This plenum is considered as a major parameter in the lab scale dump combustor design. In addition, other important design factors are the nozzle swirl number, the mixing distance, the expansion ratio of dump and nozzle area, and the acoustic impedance at a nozzle and a exhaust plug etc.
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