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와류 발생기를 장착한 가스터빈 연소기에서 연료/공기 혼합 및 NOx 배출 특성에 관한 수치적 연구
김구(Gu Kim),이영덕(Young Duk Lee),손채훈(Chae Hoon Sohn) 한국연소학회 2013 한국연소학회지 Vol.18 No.3
가스터빈용 희박 예혼합 연소기 내부에 와류 발생기(vortex generator)를 장착하여 그에 따른 연료/공기혼합 및 NOx 배출 특성 변화를 조사하였다. 이를 위해 수치해석적 방법을 채택하여 연소기내 유동특성, 연료/공기 혼합도, 배기가스(NOx), 화염형상을 분석하였다. 와류 발생기를 장착한 경우, 연소기 내부에서 와류 발생기에 의한 나사산 형상으로 인해 와류가 형성되며 이는 연소기 전면부까지 유지되었다. 또한 연소기 내부 면적 차로 인해 압력섭동이 발생하였다. 이와 더불어 연소기 전면부 기준 상류지역의 연료와 공기의 혼합도가 증가됨으로서 연료 과농지역이 감소하게 되며 이로 인해 전반적인 NOx 발생량의 감소 효과를 볼 수 있었다. 화염 형상의 변화로부터 와류 발생기의 영향으로 선회수는 다소 감소할 것으로 예상되며, 이는 와류 발생기로 인한 유속의 반복적 증감에 의한 결과라고 판단된다.
남연우(Younwoo Nam),이원남(Wonnam Lee) 한국연소학회 2010 한국연소학회지 Vol.15 No.3
In this study, soot formation characteristics on the instability of laminar diffusion flames were investigated experimentally using a concentric co-flow burner. When a small amount of air was supplied through an inner nozzle, a stable propane laminar diffusion flame became unstable and began to oscillate mainly due to the dilution effect. The increase of air flow rate transformed an oscillating non-sooting flame into a stable nonsooting flame. When the air flow rate was continuously increased an inner flame was formed and the flame was changed to an oscillating sooting flame, an oscillating non-sooting flame and finally a stable non-sooting hollow flame. When the air flow rate was decreased, a non-sooting hollow flame was eventually changed back to a stable non-sooting flame. The presence of an inner flame, however, altered the soot formation characteristics of a flame. More soot production was observed with the presence of an inner flame. The increased or decreased soot formation/oxidation rates, the radiation heat loss, and the heating effect of inner flames are most likely to be responsible for the observed instability of laminar diffusion flames.
분할형 전기히터가 장착된 디젤 매연 필터 내의 온도분포에 관한 연구
박성천(Sung-Cheon Park),이충훈(Choong-Hoon Lee),이수룡(Su-Ryong Lee) 한국연소학회 2010 한국연소학회지 Vol.15 No.3
The temperature distribution of diesel particulate filter with five partitioned electric heaters is numerically analyzed to investigate the condition of regenerating ceramic filter. The commercial code STAR-CCM+<SUP>ⓡ</SUP> is utilized to simulate multi-dimensional steady hot air flow in DPF. In order to verify the computational results, thermocouples are used to measure the temperature distribution in DPF. Computational results agree well with experimental ones. The results show that the maximum temperature in DPF is lowered as the mass flow rate of exhaust gas increases, which means that the more power in heater will be necessary as the engine speed increases. Compared with heater placed at center, heater at circumference has the higher maximum temperature in DPF. The maldistribution of flow field in front of heater has the main influence on the temperature distribution in DPF.
부분 예혼합 화염의 연소실 압력이 연료별(메탄, 에틸렌, 프로판) 연소특성과 국소 화염 반응에 미치는 영향
김종률(Jong-ryul Kim),손제하(Je-ha Son),노영구(Young-gu Noh),김윤동(Yun-dong Kim),최경민(Gyung-min Choi),김덕줄(Duck-jool Kim) 한국연소학회 2010 한국연소학회지 Vol.15 No.4
An experimental study was conducted for three different fuels(CH₄,C₂H₄ and C₃H?) to investigate the combustion characteristics and the local reaction intensity with combustor pressure(-30kpa~30kpa). Regardless of fuel composition, EINOx decreased with reducing pressure decreased. Structure and combustion characteristics were also largely affected by the combustor pressure. In addition, reaction intensity in terms of the changing combustor pressure and equivalence ratio was investigated. Combustion reaction in higher than atmospheric pressure was very active than the lower combustor pressure. When the combustor pressure is lower than the atmospheric pressure, the overall reactivity is noticeably enhanced due to the elevated diffusion process of unburned mixture. It was found that the combustion characteristics of the methane and propane flames are considerably influenced by the pressure while those of ethylene flame are less sensitive to the combustor pressure.
김태훈(Taehoon Kim),우민호(Mino Woo),김용모(Yongmo Kim) 한국연소학회 2010 한국연소학회지 Vol.15 No.4
The Direct Quadrature Method of Moments (DQMOM) has been presented for the solution of population balance equation in the wide range of the multi-phase flows. This method has the inherently interesting features which can be easily applied to the multi-inner variable equation. In addition, DQMOM is capable of easily coupling the gas phase with the discrete phases while it requires the relatively low computational cost. Soot inception, subsequent aggregation, surface growth and oxidation are described through a population balance model solved with the DQMOM for soot formation. This approach is also able to represent the evolution of the soot particle size distribution. The turbulence-chemistry interaction is represented by the laminar flamelet model together with the presumed PDF approach and the spherical harmonic P-1 approximation is adopted to account for the radiative heat transfer.
과농조건인 CH₄/CH₃Cl 예혼합화염에서 산소부화가 PAH 생성에 미치는 효과
이기용(Ki Yong Lee) 한국연소학회 2010 한국연소학회지 Vol.15 No.4
Numerical simulations of freely propagating fuel-rich CH₄/CH₃Cl premixed flames were performed at atmospheric pressure in order to understand the effect of the oxygen enrichment on the production of PAH. A chemical kinetic mechanism was used, which involved 157 gas-phase species and 1693 forward reactions. The calculated flame speeds were compared with the experiments for the flames established on the equivalence ratios of 1~1.6, the results of which were in good agreement. As the level of oxygen enrichment was increased, the concentrations of one or four ring aromatic hydrocarbons were decreased. This might cause the fact that the contribution of PAH species to soot was weakened.
아세톤 PLIF를 이용한 가스터빈 연소기 버너 출구 연료분포의 정량적 측정
전우진(Woo-jin Jeon),김형모(Hyung-mo Kim),이강엽(Kang-yeop Lee),양수석(Su-seok Yang) 한국연소학회 2010 한국연소학회지 Vol.15 No.4
A non-intrusive measurement, Planar Laser Induced Fluorescence was employed to visualize and measure the fuel distribution of the non-reacting field at the burner exit of gas turbine combustor. Measurement techniques, image processing method and quantification procedure were presented. Also, concentration measurement with gas analyzer was carried out to verify the propriety of PLIF result. The PLIF result coincides well with gas analyzer measurement result. PLIF test result for several other conditions are mentioned as well.
심성훈(Sung Hoon Shim),정상현(Sang Hyun Jeong) 한국연소학회 2010 한국연소학회지 Vol.15 No.3
Combined technique of burner and DOC has been used for regeneration of Diesel Particulate Filter. Experiments has been performed to increase the temperature of engine exhaust gas to burn the collected soot in DPF at all conditions of operation of 3 liter diesel engine. Ignition temperature of soot can be successfully obtained by heats of burner flame and residual fuel oxidation at diesel oxidation catalyst even in the condition of oxygen deficiency. It is found that the load of air compressor and heat loss can be reduced to the level of practical application. It is also found that CO and THC emissions are not increase by additional combustion of regeneration burner.
Hyun Gu Roh,Seuk Cheun Choi,Chang Sik Lee 한국연소학회 2010 한국연소학회지 Vol.15 No.3
The purpose of this paper is to investigate the effects of fuel injection strategy and engine load on the structure and emissions characteristics of a DI diesel engine with 1.6L of piston displacement. In order to analyze the particulate matter (PM) and exhaust emissions characteristics in a direct injection diesel engine, the quantity of PM and exhaust emissions (including HC, CO and NOX) were investigated under various injection strategies and engine loads. Two different injection strategies (one pilot/main injection and two pilots/main injection) was investigated under the various engine loads. A thermophoretic sampling method with a scanning electron microscope (SEM) were used to obtain the PM morphology (including primary particles, the size of the agglomerates, the number of agglomerates, the fractal dimension). The quantity of soot gradually increased with increasing engine load at both injection strategies. The primary particles in the PM agglomerates indicate that the average of the primary particle and radius of gyration increased as the engine load increased.