• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.201-206
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• 2005

In order to realistically represent the complex turbulence-chemistry interaction at the partially premixed turbulent lifted flames encountered in the gas turbine combustors, the combined conserved-scalar/level-set flamelet approach has been adopted. The parallel unstructured-grid finite-volume method has been developed to maintain the geometric flexibility and computational efficiency for the solution of the physically and geometrically complex flows. Special emphasis is given to the swirl effects on the combustion characteristics of the lean-premixed gas turbine combustor. Numerical results suggest that the present approach is capable of realistically simulating the combustion characteristics for the lean-premixed gas turbine engines and the lifted turbulent jet flame with a vitiated coflow.

• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.2087-2098
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• 2003

The development of numerical mathematical model to calculate both the static and dynamic characteristics of a multi-shaft gas turbine consisting of a single combustion chamber, including advanced cycle components such as intercooler and regenerator is presented in this paper. The numerical mathematical model is based on the simplified assumptions that quasi-static characteristic of turbo-machine and injector is used, total pressure loss and heat transfer relation for static calculation neglecting fuel transport time delay can be employed. The supercharger power has a cubical relation to its rotating velocity. The accuracy of each calculation is confirmed by monitoring mass and energy balances with comparative calculations for different time steps of integration. The features of the studied gas turbine scheme are the starting device with compressed air volumes and injector's supercharging the air directly ahead of the combustion chamber.

• 한국분무공학회지
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• 제19권3호
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• pp.101-108
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• 2014

The current paper reviews the main characteristics and the operating principles of major fuel atomizers used for gas turbine combustors, including various empirical SMD equations for each atomizers. We have summarized various methodologies for evaluation of the combustion efficiency and for combustor sizing from the selected SMD data. It is found that the combustor sizing as well as the combustion efficiency are totally dependent upon the SMD calculation results, which means that special cares should be taken in choosing the SMD empirical equations.

• 한국연소학회지
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• 제5권1호
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• pp.55-66
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• 2000

A general purpose program for the analysis of flows in a gas turbine combustor is developed. The program uses non-staggered grids based on finite volume method and the cartesian velocities as primitive variables. A flow inside the C-type diffuser is simulated to check the boundary fitted coordinate. The velocity profiles at cross section agree well with experimental results. A turbulent diffusion flame behind a bluff body is simulated for the combustion simulation. Simulated results show good agreement with experimental data. Finally, a turbulent flow with swirl in a gas turbine combustor was simulated. The results show two recirculating region and simulated velocity fields agree well with experimental data. The distance between two recirculating regions becomes shorter as swirl angle increases. Swirl angle changes angular momentum and streamlines in flow fields.

• 한국연소학회지
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• 제18권3호
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• pp.54-60
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• 2013

This paper shows a general development process for aircraft gas turbine combustors. As a first step for developing the preliminary combustor design program, several combustor sizing methodologies using reference area concepts are reviewed. There are three ways to determine the reference area; 1) combustion efficiency approach, 2) pressure loss approach, 3) velocity assumption approach. The current study shows the comparisons of the calculated results of combustor reference values from the pressure loss and velocity assumption approaches. Further works are required to add iterative steps in the program using more reasonable values of pressure loss and velocities, and to evaluate the sizing results using data for actual combustor performance and sizes.

• 한국연소학회지
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• 제18권3호
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• pp.61-67
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• 2013

This study introduces the design methods for air flow distribution at the level of preliminary design, and reviews the typical combustion process and main functions of sub-components of aircraft gas turbine combustors. There are lots of design approaches and empirical equations introduced for air flow distributions at the combustors. It is shown that a decision on which design approaches work for the combustor development is totally dependent upon the objective of engine design, target performance, and so on. The current results suggested for preliminary air flow distributions need to be validated by combustor geometry checkups and performance evaluations for future works.

• 한국분무공학회지
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• 제27권1호
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• pp.36-41
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• 2022

In this study, the combustion instability characteristics according to the change in the hydrogen ratio in the fuel in the single nozzle system of the hydrogen-natural gas mixed gas turbine for power generation was analyzed using a three-dimensional finite element analysis-based Helmholtz solver. This combustor shows the instability characteristics in which mode transition occurs from a mode having a low amplitude near 70 Hz to a mode having a high amplitude of 250 Hz or higher as the hydrogen fraction in the fuel increases. The current modeling results are found to reasonably predict the main characteristics of the change in measured instability frequency and growth rate with the change in fuel composition.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3264-3269
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• 2007

Combustion instability is a serious obstacle for the lean premixed combustion of gas turbines, and can even cause fatal damage to the combustor and the entire system. Thus, improved understanding of the mechanisms of combustion instability is necessary for designing and operating gas turbine combustors. In this study, in order to understand the instability phenomena, an experimental study was conducted in a rearwardstep dump combustor with LPG and air. The fluctuations of pressure and heat release were measured by piezoelectric pressure sensor and High speed Intensified Charge Coupled Device (ICCD) camera respectively. Various types of combustion modes occurred in accordance with the equivalence ratio and the fuel supplying conditions. The unmixedness of the fuel and air can be controlled by changing the mixing distance ($L_{fuel}$). It is found that the unmixedness of the fuel and air affects the characteristics of flame behavior and pressure fluctuations in a lean premixed flame.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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• pp.129-132
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• 2008

30톤급 액체로켓엔진 가스발생기의 연소 특성에 대한 연구를 수행하였다. 개발 초기 가스발생기는 터빈 매니폴드 출구를 모사하는 노즐을 후단에 장착한 상태에서 연소시험을 진행하였다. 이후 가스발생기와 터빈부의 공진모드를 모사하는 연장배관을 가스발생기와 노즐 사이에 추가하여 시험이 이루어졌으며, 최종적으로 터보펌프의 터빈부를 연결한 상태에서 연소시험을 수행하였다. 본 논문에서는 이와 관련된 온도 분포, 압력섭동 결과들을 분석하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 춘계학술대회 논문집
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• pp.263-266
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• 2009

본 연구는 GE 7FA+e DLN 2.6 가스터빈 연소기를 축소 제작한 모형 가스터빈 연소기의 연소 동특성 및 연소불안정 현상을 알아보고 위해 진행되었다. 모형 연소기에 사용된 연료노즐은 1/3 크기로 상사하여 제작되었으며, 실제 연료노즐과 동일한 2단 스월러(swirl vane)를 가지고 있다. Plenum과 연소기의 형상은 실 가스터빈과 유사한 음향학적 특성을 가질수 있도록 설계되었다. 실험은 공기온도 $200{\sim}400^{\circ}C$, 대기압, 노즐출구 속도 $30{\sim}75\;m/s$, 당량비 $0.4{\sim}1.2$, 연소실 길이 $375{\sim}700\;mm$,에서 이루어졌으며, 그 결과 소염영역 근처의 저 당량비 영역과 당량비 1.1 이상인 연료 과농 상태에서 연소 불안정 현상이 관찰 되었다.