• 한국연소학회:학술대회논문집
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• 한국연소학회 2013년도 제46회 KOSCO SYMPOSIUM 초록집
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• pp.109-110
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• 2013

This paper describes gas turbine combustion characteristics of synthetic natural gas which contains a small amount hydrogen content. By conducting ambient pressure high temperature combustion test at gas turbine relevant combustor geometry, the combustion characteristics such as combustion instability, NOx and CO emission, temperatures at turbine inlet, nozzle and dump plane, and flame structure from high speed OH chemiluminescence images were investigated when changing hydrogen content from zero to 5%. From the results, qualitative and quantitative relationships are derived between key aspects of combustion performance, notably NOx/CO emission and combustion instability. Natural gas containing hydrogen up to 5% does not show significant difference in view of all combustion characteristics except combustion instability. Only up to 1% hydrogen addition could not change the pressure fluctuation and phase gas between fluctuations of pressure and heat release. From the results, it can be concluded that synthetic national gas which contains 1% of hydrogen can be guaranteed for the stable and reliable operation of natural gas firing gas turbine.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2946-2951
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• 2008

Combustion instability is a major issue in design of gas turbine combustors for efficient operation with low emissions. Combustion instability is induced by the interaction of the unsteady heat release of the combustion process and the change in the acoustic pressure in the combustion chamber. In an effort to develop a technique to predict self-excited combustion instability of gas turbine combustors, a new stability analysis method based on the transfer matrix method is developed. The method views the combustion system as a one-dimensional acoustic system with a side branch and describes the heat source as the input to the system. This approach makes it possible to use the advantages of not only the transfer matrix method but also well-established classic control theories. The approach is applied to a simple gas turbine combustion system to demonstrate the validity and effectiveness of the approach.

• Journal of Mechanical Science and Technology
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• 제17권6호
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• pp.906-913
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• 2003

Lean premixed combustion has been considered as one of the promising solutions for the reduction of NOx emissions from gas turbines. However, unstable combustion of lean premixed flow becomes a real challenge on the way to design a reliable, highly efficient dry low NOx gas turbine combustor. Contrary to a conventional diffusion type combustion system, characteristics of premixed combustion significantly depend on a premixing degree of combusting flow. Combustion behavior in terms of stability has been studied in a model gas turbine combustor burning natural gas and air. Incompleteness of premixing is identified as significant perturbation source for inducing unstable combustion. Application of a simple convection time lag theory can only predict instability modes but cannot determine whether instability occurs or not. Low frequency perturbations are observed at the onset of instability and believed to initiate the coupling between heat release rate and pressure fluctuations.

• 한국연소학회지
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• 제13권3호
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• pp.33-40
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• 2008

Two- and Three- dimensional numerical simulations are carried out to understand the combustion characteristics of LNG-fueled gas turbine combustor for power generation using imported and domestic natural gases. Reacting flow characteristics of the swirl stabilized natural gas combustor were understood from the numerical results with the flow conditions selected from the gas turbine operation data. The thermal influences of different natural gases were very small and the fuel composition and flow rate were considered to be tuned well. The flow structures of the recirculation and combustion region was understood from the comparison of the two- and three-dimensional results. The complexity of the three-dimensional swirl flows inside the gas turbine combustor with multiple swirlers was understood those resulting from the interactions of the stage and pilot burners.

• 한국연소학회지
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• 제20권4호
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• pp.10-18
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• 2015

Combustion instability is a major issue in design and maintenance of gas turbine combustors for efficient operation with low emissions. With the thermoacoustic view point the instability is induced by the interaction of the unsteady heat release of the combustion process and the change in the acoustic pressure in the combustion chamber. In an effort to study the combustion dynamics of gas turbine combustors, Morgans et al (2014) have developed OSCILOS (open source combustion instability low order simulator) code and it is currently available online. In this study the code has been utilized to predict the combustion instability of a reported case for lean premixed gas turbine combustion, and then its prediction results have been compared with the corresponding experimental data. It turned out that both the predicted and the experimental combustion instability results agree well. Further the effects of some typical inlet acoustic boundary conditions on the prediction have been investigated briefly. It is believed that the validity and effectiveness of the open source code is reconfirmed through this benchmark test.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.59-60
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• 2012

This paper describes gas turbine combustion characteristics of synthetic gas which is mainly composed of hydrogen and carbon monoxide. The combustion characteristics such as combustion instability, NOx and CO emission, temperatures at turbine inlet, liner and dump plane, and flame structure were investigated when changing when changing $H_2:CO$ ratio, dilution ratio, and $CH_4:syngas$ ratio. From the results, quantitative relationships are derived between key aspects of combustion performance, notably NOx emission. It is concluded that NOx emission of syngas is strongly influenced by the diluent heat capacity and combustion instability. Moreover, NOx control method using diluents such as $N_2$, $CO_2$, steam is verified.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1682-1685
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• 2004

Gas Turbine combustors for power plant can be reduced NOx emissions using lean premixed combustion technology. But the combustors are likely to occur combustion oscillations which damage operation reliability and mechanical life of the gas turbines. In this paper, characterizations of oscillation in a gas turbine combustor for power plant are presented. Combustion dynamics occur $1{\sim}1.5$ psi in amplitude with low frequency less than 140Hz during normal operation. An abnormal high level dynamics, 2.0 psi amplitude occur at 125 Hz frequency. Abnormal combustion oscillation is reduced by modulation of fuel supply valve control schedule.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3270-3275
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• 2007

DME (Dimethyl Ether, $CH_3OCH_3$) has highly attracted attention as an alternative fuel for transportation, power generation and LPG substitute owing to its easy transportation and cleanliness. This study was conducted to verify the combustion performance and to identify potential problems when DME is fuelled to a gas turbine. GE7EA gas turbine of Pyong-Tak power plant was selected as a target to apply the DME. Combustion tests were conducted by comparing DME with methane, which is a major component of natural gas, in terms of combustion instability, $NO_X$ and CO emissions, and the outlet temperature of the combustion chamber. The results of the performance tests show that DME is very clean but has a low combustion efficiency in low load condition. From the results of the fuel nozzle temperature we have ascertained that DME is easy to flash back, and this property should be considered when operating a gas turbine and retrofitting a burner.

• 한국추진공학회지
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• 제19권5호
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• pp.22-30
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• 2015

개방형 사이클의 액체로켓엔진에서는 추진제 중 일부를 연소시켜 터빈 구동용 가스를 생성시키는 가스발생기가 사용되며, 개방형 사이클 액체로켓엔진의 주요 구성품으로서 가스발생기 자체의 연소성능 및 특성을 파악하기 위한 연소시험이 요구된다. 하지만, 가스발생기에서 생성된 연소가스는 터빈 매니폴드의 터빈 노즐에서 질식이 이루어지기 때문에 가스발생기뿐만 아니라 터빈 매니폴드 내부 부피를 고려해야만 가스발생기의 연소 성능 및 특성, 그리고 음향 특성을 정확히 파악할 수 있다. 따라서, 본 논문에서는 터빈 매니폴드 모사장치를 이용한 가스발생기 연소시험 결과를 기술하고 가스발생기 단독 연소시험 결과를 이용한 특성 예측을 설명한다.

• 설비공학논문집
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• 제22권3호
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• pp.156-164
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• 2010

Combustion instability is a major issue in design of gas turbine combustors for efficient operation with low emissions. Combustion instability is induced by the interaction of the unsteady heat release of the combustion process and the change in the acoustic pressure in the combustion chamber. In an effort to develop a technique to predict self-excited combustion instability of gas turbine combustors, a new stability analysis method based on the transfer matrix method is developed. The method views the combustion system as a one-dimensional acoustic system with a side branch and describes the heat source as the input to the system. This approach makes it possible to use not only the advantages of the transfer matrix method but also well established classic control theories. The approach is applied to a gas turbine combustion system, which shows the validity and effectiveness of the approach.