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끝벽의 설치 위치 및 변형 높이에 따른 환형 터빈 노즐 안내깃 캐스케이드 내 3차원 유동에 미치는 영향에 관한 수치해석
이우상(Wu Sang Lee),김대현(Dae Hyun Kim),민재홍(Jae Hong Min),정진택(Jin Taek Chung) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
Endwall losses contribute significantly to the overall losses in modern turbomachinery, especially when aerodynamic airfoil load and pressure ratio are increased. Hence, reducing the extend and intensity of the secondary flow structures helps to enhance overall efficiency. From the large range of viable approaches, a promising combination positioning and height of endwall contouring was chosen. The objective of this study is to document the three-dimensional flow in a turbine cascade in terms of streamwise vorticity, total pressure loss distribution and static pressure distribution on the endwall and blade surface and to propose an appropriate positioning and height of the endwall contouring which show best secondary, overall loss reduction among the simulated endwall. The flow through the gas turbine were numerically analyzed using three dimensional Navier-Stroke equations with a commercial CFD code ANSYS CFX-10. The result shows that the overall loss is reduced near the flat endwall rather than contoured endwall, and the case of contoured endwall installed at 30% from leading edge with height of 25% for span showed best performance.
끝벽의 형상이 터빈 캐스케이드 내열전달 특성에 미치는 영향에 관한 전산해석
이우상(Wu sang Lee),윤덕규(Deok kyu Yoon),곽현주(Hyun ju Kwag),정진택(Jin Taek Chung) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-
The Objective of this study is to document the three-dimensional flow in a turbine cascade with Contoured endwall in terms of Stanton number distribution to proposes an appropriate contraction ratio of endwall contouring which show the best performance. This study was numerically performed. The results show that heat transfer coefficient on the contoured endwall which has the height of 15% of the axial chord showed best performance. The numerical method and results in this study can be applied to the design of gas turbine cascade with high performance.
자유유동 난류강도가 터빈 캐스케이드내 3차원 난류유동 특성에 미치는 영향에 관한 전산해석
윤덕규(Deok-Kyu Yoon),이우상(Wu Sang Lee),김대현(Dae Hyun Kim),정진택(Jin Taek Chung) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-
The objective of this study is to determine the influence of free-stream turbulent intensity on the three-dimensional turbulent flow in a linear turbine cascade. The range of free-stream turbulence intensity considered is 0.7~10%. This study was performed numerically. The results show that the mass averaged loss coefficient increased according to the increase of free-stream turbulence intensity due to increased value of the mass averaged total pressure loss coefficient which was higher than the decreased value of the mass averaged secondary flow loss coefficient. The loss coefficient distribution was changed suddenly at a free-stream turbulence intensity of 10% while the loss coefficient distribution was rarely changed at a lower free-stream turbulence intensity of 5%.
축류 가스터빈내 동익의 허브면에 장착된 경계층 펜스의 효과에 대한 수치 해석적 연구
윤덕규(Deok-Kyu Yoon),이우상(Wu Sang Lee),김대현(Dae Hyun Kim),정진택(Jin Taek Chung) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-
The objective of this study is to investigate the effects of the boundary layer fence equipped on the hub of the rotor in an axial gas turbine which occurs the interaction between the stator and rotor. The complicate three-dimensional flows in an axial gas turbine cause secondary loss and increase the total pressure loss. In order to reduce or control these secondary flows, the boundary layer fence which has the height of one third of the inlet boundary layer thickness was equipped on the hub of the rotor. This study was performed numerically. The result shows that wake generated by the stator reduces the development of secondary flow in the rotor blade passage but doesn't interrupt the formation of horseshoe vortex generated in front of the rotor blade leading edge. Although boundary layer fence gives rise to additional loss, it can reduce total pressure loss compared to the case without fence by enervating downstream secondary vortices.
김중석(Joung-seok Kim),이우상(Wu-sang Lee),류제욱(Je-wook Ryu) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
This paper describes the aerodynamic design procedure for axial turbines of small heavy duty gas turbine engines being developed by Doosan Heavy Industries. The design procedure consists of mainly three parts, namely, flowpath design, airfoil design, and 3D performance calculation. To design the optimized flowpath, throughflow calculations, as well as the loss estimation, are widely used to evaluate the effect of geometric variables, e.g. shape of meridional plane, mean radius, blades axial gap, hade angle, etc. During airfoil design procedure, the optimum blade count is calculated by empirical correlations based on in/outlet flow angles, and then 2D airfoil planar sections are designed carefully, followed by 2D B2B NS calculations. The designed planar sections are stacked along span direction, leading to 3D surface airfoil shape. To consider 3D effect on turbine performance, 3D multistage Euler calculation, single row and multistage NS calculations are performed.
1단 축류 터빈의 정익/동익 상호작용하에서 축 간격에 따른 동익내 열전달 특성에 관한 수치해석
윤덕규(Deok Kyu Yoon),이우상(Wu Sang Lee),김대현(Dae Hyun Kim),정진택(Jin Taek Chung) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
The objective of this study is to investigate the heat transfer characteristics on the rotor blade with the wake from the stator in an axial turbine stage which has the interaction between the stator and rotor blade. This study was performed numerically and dimensionless St number to represent the degree of heat transfer was calculated on the hub, shroud and blade suction surface as the distance variation between stator and rotor blade. The results show that heat transfer on the hub and blade suction surface was decreased as the distance between stator and rotor blade increases because the wake from the stator was decreased by friction on the hub, shroud and the passage vortex in the rotor stage. When the wake from the stator run into the leading edge of the rotor, the heat transfer on the suction surface occurred the most actively; however, heat transfer near the trailing edge was little decreased by the flow separation.
김중석(Joung Seok Kim),이우상(Wu Sang Lee),류제욱(Je Wook Ryu) 대한기계학회 2013 大韓機械學會論文集B Vol.37 No.4
본 논문은 두산중공업㈜에서 개발 중인 소형 가스터빈의 축류 터빈 설계 과정을 기술하였다. 축류 터빈의 설계 과정은 크게 유로설계, 익형설계, 3D 성능 계산의 세 단계로 구성되며. 최적의 유로를 설계하기 위해 자오면의 형상, 평균 반경, 블레이드간 간격, 유로 형상각 등 여러 형상 변수에 대해 통과유동계산 및 손실계산을 수행한다. 익형 설계는 유로 설계시 스팬 방향으로 계산된 입출구 유동각을 기준으로 실험상관식을 적용하여 최적의 블레이드 개수를 결정한 후 2D 익형 단면을 설계하며 2D NS 계산을 통해 캐스케이드 유동구조를 검토하여 설계한 단면의 설계적정성을 평가한다. 설계된 2D 익형 단면을 스팬 방향으로 적층하여 3D 익형을 생성하고, 다단 Euler 계산, 단익렬, 다단 NS 계산을 수행하여 3D 유동 특성을 고찰한다. This study describes the aerodynamic design procedure for the axial turbines of a small heavy-duty gas turbine engine being developed by Doosan Heavy Industries. The design procedure mainly consists of three parts: namely, flowpath design, airfoil design, and 3D performance calculation. To design the optimized flowpath, throughflow calculations as well as the loss estimation are widely used to evaluate the effect of geometric variables, for example, shape of meridional plane, mean radius, blades axial gap, and hade angle. During the airfoil design procedure, the optimum number of blades is calculated by empirical correlations based on the in/outlet flow angles, and then 2D airfoil planar sections are designed carefully, followed by 2D B2B NS calculations. The designed planar sections are stacked along the spanwise direction, leading to a 3D surfaced airfoil shape. To consider the 3D effect on turbine performance, 3D multistage Euler calculation, single row, and multistage NS calculations are performed.