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복합발전 가스터빈 연소기용 저선회 노즐의 연료 분사 위치에 따른 배기배출 및 연소진동 특성
황정재,이원준,김민국,김한석 한국가스학회 2022 한국가스학회지 Vol.26 No.6
Many researches and developments are being conducted to achieve the higher efficiency of the combined cycle gas turbine, and one of them is to increase the efficiency by achieving a higher combustion temperature. To this end, many combustor nozzles and combustion technologies have been developed, and low-swirl nozzles are one of them. In this study, two low-swirl nozzles with the same SN (Swirl Number) but different mass ratio (m) of the core part and the swirler part were designed to perform an atmospheric pressure combustion test. For each nozzle, a combustion test was conducted according to the adiabatic flame temperature, and the flame structure, emissions, and combustion dynamics mode were identified. Although the flame structure was significantly different, the CO emission was similar, and the NOx emission was also more related to combustion dynamics than the flame structure. Combustion dynamics and NOx emission were identified while adjusting the convection delay time by changing the position of the fuel injection nozzle, and the combustion dynamics analysis method using the time-delay analysis method was confirmed to work. 복합발전용 가스터빈의 더 높은 효율을 달성하기 위해 많은 연구개발이 이루어지고 있고 그 중 하나가 더 높은 연소온도를 달성하여 효율을 높이는 것이다. 이를 위해 많은 연소 노즐 및 연소기술들이 개발되고 있으며 저선회 노즐도 그 중 하나이다. 본 연구에서는 SN(Swirl Number)는 같지만 코어부와 스월러부의 질량유량비(m)가 다른 저선회 노즐 2종을 설계하여 상압 연소성능 시험을 수행하였다. 각 노즐에 대해 단열화염온도에 따른 연소성능 실험을 수행하였고 화염구조 특성, NOx 배출 특성, 연소진동 모드를 파악하였다. 화염구조가 크게 차이가 있었지만 CO 성능은 유사하였고 NOx 성능도 화염구조보다는 연소진동과 더 큰 관련성이 있음을 보였다. 연료노즐의 위치를 변경하여 대류지연시간을 조절하면서 연소진동 및 NOx 특성을 파악하였는데 시간지연 분석법에 의한 연소진동 분석법이 작동함을 확인하였다.
H2/CO 합성가스 비예혼합 난류 제트화염에서 부착화염의 화염안정화
황정재,Nicolas Bouvet,손기태,윤영빈 한국연소학회 2012 한국연소학회지 Vol.17 No.1
The detachment stability characteristics of syngas H2/CO jet attached flames were studied. The flame stability was observed while varying the syngas fuel composition, coaxial nozzle diameter and fuel nozzle rim thickness. The detachment stability limit of the syngas single jet flame was found to decrease with increasing mole fraction of carbon monoxide in the fuel. In hydrogen jet flames with coaxial air, the flame detachment stability was found to be independent of the coaxial nozzle diameter. However, velocities of appearance of liftoff and blowout velocities of lifted flames have dependence. At lower fuel velocity range, the critical coaxial air velocity leading to flame detachment increases with increasing fuel jet velocity, whereas at higher fuel velocity range, it decreases. This increasing-decreasing non-monotonic trend appears for all H2/CO syngas compositions (50/50 ~ 100/0% H2/CO). To qualitatively understand the flame behavior near the nozzle rim, OH* chemiluminescence imaging was performed near the detachment limit conditions. For all fuel compositions, local extinction on the rim is observed at lower fuel velocities (increasing stability region), while local flame extinction downstream of the rim is observed at higher fuel velocities (decreasing stability region). Maximum values of the non-monotonic trends appear to be identical when the fuel jet velocity is normalized by the critical fuel velocity obtained in the single jet cases.
황정재,김민국,이원준,민경욱,강도원,김한석 한국연소학회 2023 한국연소학회지 Vol.28 No.4
Axial fuel staging (AFS) nozzle variants for applying to heavy duty gas turbine combustors were designed and experimentally investigated in this study. Four AFS nozzle variants (elliptic, dual elliptic, airfoil, and low-swirl type) were designed and single AFS nozzle test was conducted at the 1/4-scale combustion test rig with measurement module consists of 25-points emissions and 30-points exit temperatures. Flame structures were observed with OH-Planar Laser Induced Fluorescence (PLIF) and direct photo. When the fuel split was about 120% of the air split, NOx emission was minimum which is about 80% of the reference. Flame penetration was increased with air split and temperature profile pattern factor was found to be the lowest in dual elliptic nozzle. Four dual elliptics nozzles were mounted in the middle of the can combustor to conduct the full-can combustion test. Minimum NOx emissions were found at 10.4% fuel split, which is 120% of air dsplit.
황정재,조은성,김민국,이원준,Borys Shershnyov,신영준 한국연소학회 2022 한국연소학회지 Vol.27 No.4
A hydrogen combustor for applying to 5MWe-class small gas turbines was designed and experimentally investigated in this study. A swirl type, not a multi-tube type, which is widely used in the recently developed hydrogen combustor, was applied to this hydrogen combustor. The test was conducted at the inlet temperature of 410°C which is derived from cycle analysis and at atmospheric pressure (1.35 barA). First, the ignition test was performed while switching from NG flame to hydrogen flame. Flame structures (from direct photo and OH* chemiluminescence), NOX emission and dynamic pressure were observed with varying adiabatic flame temperatures and fuel splits of FC1 and FC2. Lean blowout and flashback characteristics were investigated with varying equivalence ratio and flow velocity. Flame was converted from V-shaped flame to M-shaped flame as equivalence ratio increases and M-shaped one has higher NOX emissions. NOX emission is under 3 ppm (@15% O2) at 1860 K of flame temperature which is equivalent or even lower level of NG combustors. It was found that the operating range from lean blowout to flashback is very wide.
GT24 가스터빈용 EV 버너의 수소혼소에 따른 질소산화물 배출 특성에 대한 실험적 연구
황정재,이원준,민경욱,강도원,김한석,김민국 한국가스학회 2023 한국가스학회지 Vol.27 No.4
In response to climate change, each country is proposing a goal to reduce greenhouse gases in its energy supply and demand plan, and the use of hydrogen gas is a topic that is always prioritized as an energy resource for implementation. A popular way to use this hydrogen gas is the use of hydrogen fuel cell vehicles, and expansion of hydrogen charging stations is essential for using these hydrogen fuel cell vehicles. However, there are several limitations to the expansion of hydrogen refueling stations, the most representative of which is resident acceptance. Most of the hydrogen charging stations currently built in Korea are located in the outskirts with low population density, so the inconvenience to hydrogen fuel cell vehicle users has not been resolved, and as a result, there has been no progress in the spread of hydrogen fuel cell vehicles. In this paper, we analyzed the consequences of accident damage to determine the risks of constructing a hydrogen charging station on a railroad site frequently used by citizens. The target hydrogen charging station site was a railroad depot in Busan, and there are trains, national highways, and commercial facilities around this site. Assuming the worst-case scenario, we would like to consider the safety of the hydrogen refueling station site by analyzing the area affected by the accident and its consequence.
동축공기 유동장에서 수소 난류확산 부상화염의 안정화 연구
황정재(Jeongjae Hwang),오정석(Jeongseog Oh),백경엽(Kyong-Yup Paik),윤영빈(Youngbin Yoon) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.40
To understand hydrogen jet liftoff height, the stabilization mechanism of turbulent lifted jet flames under non-premixed conditions was studied. The objectives were to determine flame stability mechanisms, to analyze flame structure, and to characterize the lifted jetat the flame stabilization point. Hydrogen flow velocity varied from 100 to 300 ㎧. Coaxial air velocity was regulated from 12 to 20 ㎧. Simultaneous velocity field and reaction zone measurements used, PIV/OH PLIF techniques with Nd:YAG lasers and CCD/ICCD cameras. Liftoff height decreased with increased fuel velocity. The flame stabilized in a lower velocity region next to the faster fuel jet due to the mixing effects of the coaxial air flow. Lifted flame stabilization was related to local principal strain rate and turbulent intensity, assuming that combustion occurs where local flow velocity and turbulent flame propagation velocity are balanced.