• Journal of the KSME
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• v.34 no.12
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• pp.929-939
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• 1994

최근 환경문제와 관련하여 정제된 석유 연료가 아닌 천연가스와 같은 연료의 사용이 증가하면서 산업용 가스터빈의 연소기술에 대한 관심이 집중되고 있다. 가스터빈 연소로 생성되는, 환경을 위협하는 오염물은 연기, 수증기, 일산화탄소(CO), 미연 탄화수소, $NO_{x}$, $SO_{x}$ 등이 있다. 수증기 및 일산화탄소는 지구 온실화에 영향을 미치고 있으나 그다지 심각한 정도는 아 니며, $SO_{x}$는 독성이 있으나 연료 정제시 제거되어질 수 있다. $NO_{x}$는 지구의 오 존층을 파괴하여 생태계를 위협하기 때문에 오염 배출물중 가장 심각하게 고려되어지고 있다. 미국에서는 법으로 산업용 가스터빈의 $NO_{x}$의 양을 규제하고 있는데 15% 산소배출농도에 대하여 1984년에 75ppm에서 1993년에 30ppm으로 낮추어 규제하고 있다. 일본도 미국과 비슷한 수준으로 규제하고 있으며, 따라서 최근의 가스터빈 연소기술은 저 $NO_{x}$연소기에 대한 것으로 저$NO_{x}$연소에 관한 개론 및 가스터빈 연소기의 저$NO_{x}$화 방법, 그리고 미 국과 일본의 최근의 저$NO_{x}$연소기 개발동향에 대하여 다루고자 한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.405-406
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• 2008

Combustor is one of the major component of gas turbine engine and its development is done mostly by performance test. Combustors for aviation gasturbine engines has been successfully tested at the test facility in KARI as well as for stationary gasturbine engines. Full scale combustor test requires large amount of high temperature and pressure air, so the test facility is equipped with big air compressor and heater.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.401-405
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• 2011

Although the APU combustors were developed successfully, it could face many unexpected hardships in a engine or a system operated under the severe environment. This study is to be verified and settled by experimently and analytically of the problems and issues occurred in a variety of engine and system operation tests.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.381-386
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• 2007

Jet-A spray, evaporation and combustion were numerically analyzed in annular type model combustor using KIVA-3V. Liquid fuel's atomizing was affected by flow field near droplet. When cooling flow was not optimized, SMD was increased, and equivalence ratio was horizontally distributed in combustor's downstream. Flame spread out horizontally and separated in combustors downstream. Flame center was separated by cooling flow. Flame separation made local high temperature in downstream that caused NO increase.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.5
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• pp.51-59
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• 2008

DLN-2.6 combustion tuning was carried out for the maintenance of GE 7FA+e gas turbine at Seo-Incheon combined cycle power plant. DLN-2.6 combustion system has the higher level of yellow plume and combustion vibration problem in the initial operating mode than that of the base mode($100{\sim}160MW$). The objectives of this study are to investigate the causes of yellow plume and combustion vibration problems at the starting mode and to suggest the best operating condition for the reliable working of the real combustors. By the analysis of tuning data, we could conclude that a yellow plume is caused by the rich mixture(${\phi}{\sim}1$) in a PM 1 nozzle at mode 3($20{\sim}30MW$). In addition, the combustion vibration($120{\sim}140Hz$) might be related to the cold flow characteristics of PM 3 nozzles at mode 6B($40{\sim}45MW$).

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.3
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• pp.50-57
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• 2009

A gas mechanical pulsator is developed for the study of combustion instabilities in various combustors such as LRE combustor. First, it shows that the mass flow rates and the perturbation frequencies can be successively controlled by the inlet pressure and the rotating speed of a rotating disk with many holes. Second, the device is used as an acoustic amplification source as a substitute for the speaker in the previous acoustic tests and its results show almost the same resonant frequency and damping characteristics compared with the previous results. In conclusion, the result shows that it can be used as a substitute for a speaker in the studies of LRE combustion instabilities, which has a flow and no limitation of amplification, and a device for making a perturbation source in gas flow.

• The Journal of the Acoustical Society of Korea
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• v.18 no.7
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• pp.56-66
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• 1999

Thermoacoustic oscillation is a significant problem in cylindrical-type combustors such as common internal combustion engines, industrial furnaces, gas turbine, etc. This kind of low frequency oscillation can lead to serious consequences such as destruction of the combustor and production of strong noise. The accurate numerical simulation of thermoacoustic phenomena is a complex and challenging problem, especially when considering the chemical reaction of mixtures. As with other simulations of aerodynamics and aeroacoustics, the direct computation of thermoacoustic phenomena requires that Navier-Stokes equations be solved using accurate numerical differentiation and time-marching schemes, with non-reflecting boundary conditions. The numerical approach used here aims at qualitative analysis and efficient prediction of those problems, not at the development of an accurate scheme. The numerical prediction developed in this work is shown to be reasonably matched with experimental result.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.6
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• pp.171-178
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• 2006

The performance in the practical combustion system including reciprocating engines and gas turbine combustors is being much governed by turbulent reacting flow that is often analyzed by both a laminar flamelets concept and flame interaction. The characteristics of laminar flame interaction have been investigated numerically to provide basic understanding of wrinkled turbulent flames under concentration interaction resulting from inhomogeneity in fuel-air mixing, especially focused on the transition of flame characteristics such as diffusion flame, partially premixed diffusion flame, and triple-layer flame by the variation in the degree of premixedness. The extinction stretch rates to the premixedness have also been obtained in this paper. The boundary defining the regime of the existence of triple-layer flames as functions of both stretch rate and premixedness has been determined which agrees well with previously reported experiment measuring OH radical concentration peaks based on PLIF.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.9
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• pp.658-665
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• 2009

Lean premixed combustors are used for significant NOx reduction which one of issues in current gas turbine combustor. This study was investigated to estimate the effects of the unmixedness of fuel-air, equivalence ratio on the instability mechanism, NOx emission and combustion oscillation in a lean premixed combustor. The experiments were conducted in a dump combustor at atmospheric pressure conditions using methane as fuel. The swirler angle was $45^{\circ}$, the degrees of fuel-air mixing were 0, 50 and 100 and inlet temperature was 650K. The equivalence ratio was ranging from 0.5 to 0.8. This paper shows that NOx emission was increased when the degree of fuel-air mixing is increased in same equivalence ratio and when equivalence ratio is increased. And the range of the combustion instability was enlarged as a function of increasing of the degree of fuel-air mixing.

• Journal of the Korean Society of Combustion
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• v.3 no.1
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• pp.59-69
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• 1998

The results of study on the active control of naturally occurring combustion oscillations with a single dominant frequency in an atmospheric dump combustor are presented. Control was achieved by an oscillatory infection of secondary fuel at the dump plane. A high speed solenoid valve with a maximum frequency of 250Hz was used as the actuator and a sound level meter, located at the combustor exit, measured the pressure fluctuations which served as the feedback signal for the control loop. Instability characteristics were mapped over a range of mean mixing section velocities from 6.7 m/s-9.3 m/s and with three mixing conditions. Different fuel/air mixing conditions were investigated by introducing varying percentages of primary fuel at two locations, one at the entrance to the mixing section and one 6 mixing tube diameters upstream of the dump plane. Control studies were conducted at a mean velocity of 9.3 m/s, with an air temperature of $415^{\circ}C$, and from flame blowout to the stoichiometric condition.