수평축 조류발전의 수위변화에 따른 캐비테이션 특성

남상현(Sang-Hyun Nam),김정민(Jung-Min Kim),김유택(You-Taek Kim),최영도(Young-Do Choi),이영호(Young-Ho Lee) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

Presently, horizontal-axis tidal current generation that be generated by water force in the water has been developing in many companies. It can't only obtain electricity without pollution material for clean environment but also it has advantage that has economical efficiency. Therefore, horizontal-axis tidal current generation is very attracted, because of those of advantages. In order to research on horizontal-axis tidal current generation that considered process of cavitation and free surface, we have performed lots of research compared with experiment. This paper have been analyzed the influence of cavitation within a turbine blade and performance characteristics for variable water level from the bottom (H=3.6m, 3.2m) by CFD. When the turbine performance compared water level 3.6m with 3.2m, the power and efficiency is decreased at 3.2m.

다양한 TSR변화에 따른 1MW급 조류발전 터빈 블레이드 형상설계와 출력성능 예측

최현준,오영철,김범석,서광철,이영호 한국마린엔지니어링학회 2018 한국마린엔지니어링학회지 Vol.42 No.4

We designed the basic shape of a 1-MW horizontal-axis tidal-current turbine blade utilized for blade element momentum theory, which has been used generally for aerodynamic design and power performance analysis. The basic shape is a three-blade applied to NREL S814 airfoil. Tidal current turbine blades are operated by ocean current and water pressure because of the nature the marine environment and the environment should be discretely considered when designing the shape. To compare the flow characteristics and power performance of the present blade shape, computational fluid dynamics CFD analysis was performed according to the blade tip speed ratio (TSR), and the pressure coefficient and power performance were examined at each local position of the blade. The mechanical maximum power coefficient due to CFD was 48% under the condition of TSR 5. 본 논문에서는 일반적으로 블레이드 공력설계와 출력 성능해석에 활용되고 있는 날개요소운동량이론을 이용하여1MW급 수평축 조류터빈 블레이드 기본형상을 설계하였다. 기본형상은 NREL S814 에어포일을 적용한 3엽 블레이드이다. 조류터빈 블레이드는 해양환경 특성상 해류와 수압 등에서 운전되므로 형상 설계 시 신중히 고려되어야 한다. 본 블레이드 형상의 유동특성 및 출력성능을 비교 검토하기 위해 주속비 별로 CFD을 수행하였으며 블레이드의 각각의 국부위치에서 압력계수와 출력성능을 검토하였다. CFD에 의한 기계적 최대출력계수는 설계 주속비 5의 조건에서 48%로 나타났다.

Wind Turbine Simulations Using CPU/GPU Heterogeneous Computing

정용수,James Baeder 한국항공우주학회 2024 International Journal of Aeronautical and Space Sc Vol.25 No.2

In this study, a heterogeneous solution framework using both CPUs and GPUs was used to numerically simulate flow over the National Renewable Energy Laboratory (NREL) Phase IV horizontal-axis wind turbine. An in-house line-based unstructured flow solver implemented on CPUs was coupled to an in-house structured solver implemented on GPUs via a lightweight Python-based framework within an overset mesh system. First, computations were conducted for an isolated rotor at three different wind speeds of 7 m/s, 10 m/s, and 20 m/s, and subsequently full wind turbine simulations that included the nacelle and the tower. The entire system was used to understand the blade–tower interference on both upwind and downwind configurations, and the predictions were compared with the experimental data in terms of blade airloads. The effects of the laminar–turbulent transition were also investigated on a blade using the two-equation transition model coupled with Spalart– Allmaras turbulence model, whose inclusion resulted in a more accurate torque prediction. The downwind tower interaction was much more severe than the upwind interaction on the blade owing to its blade–wake interaction. Finally, a normal wind profile model was used to simulate the freestream wind shear during the wind turbine operation in an atmospheric boundary layer. Even a small variation in the wind speed resulted in a high level of unsteadiness in the blade airloads, which could generate vibratory loads on the wind turbine.

다몸체 역학을 이용한 수평축 풍력발전 시스템 모델링

민병문,송승호,최석우,노태수 전력전자학회 2004 전력전자학회 논문지 Vol.9 No.1

In this paper, an efficient modeling method of Horizontal-Axis Wind Turbine(HAWT) system is proposed. This method is based on representing a HAWT system as a multi-body system with several rigid bodies i.e. rotor blade, low/high speed shaft, gear system, and generator. Also, simulation software WINSIM is developed to evaluate performance of wind turbine system. Simulation results show that the proposed modeling method and simulation software are efficient and reliable. 본 논문에서는 로터 블레이드, 발전기, 로터 블레이드와 발전기에 연결된 고/저속 회전축 및 회전축간의 회전력을 전달하는 기어 시스템 등 다수의 몸체가 서로 상대적인 운동이 가능한 채 연결되어 있는 단일로터 수평축 풍력발전 시스템을 다몸체 시스템으로 간주한 후, 다몸체 역학을 이용한 풍력발전 시스템 모델링 기법을 제안하였다. 이를 기반으로 풍력발전 시스템의 성능 해석을 위한 시뮬레이터를 개발하였다. 그리고 다양한 시뮬레이션을 통해 제안된 풍력발전 시스템 모델링 기법과 시뮬레이터의 타당성을 검증하였다.

수평축 조류발전용 로터 블레이드 형상설계 및 CFD에 의한 출력성능해석

정지현(Ji Hyun Jung),김범석(Bum Suk Kim) 대한기계학회 2015 大韓機械學會論文集B Vol.39 No.8

본 연구에서는 풍력발전분야의 블레이드 공력설계 및 성능해석에 적용되고 있는 날개요소운동량 이론을 이용한 조류터빈 블레이드 형상설계 방법론을 제시하였으며, S814 단일 에어포일로 구성된 2 블레이드 형식의 1MW급 수평축 블레이드 형상설계 결과를 제시하였다. 조류터빈 블레이드는 해양환경에서 운전되는 특성 상 블레이드 팁 근방에서 캐비테이션 발생으로 인한 문제가 상존하므로, 설계초기단계에서 신중히 고려되어야 한다. 본 연구를 통해 설계된 1MW 조류터빈 블레이드의 유동특성분석 및 출력성능해석을 위해 캐비테이션 모델이 고려된 CFD 해석을 수행하였으며, 블레이드 팁 근방 흡입 면 및 압력 면에서 캐비테이션이 발생하고 있음을 확인하였다. 최대 출력계수는 설계 주속비 7의 조건에서 47%로 나타났다. We present a design methodology for horizontal-axis tidal turbine blades based on blade element momentum theory, which has been used for aerodynamic design and power-performance analysis in the wind-energy industry. We design a 2-blade-type 1 MW HATT blade, which consists of a single airfoil (S814), and we present the detailed design parameters in this paper. Tidal turbine blades can experience cavitation problems at the blade-tip region, and this should be seriously considered during the early design stage. We perform computational fluid dynamics (CFD) simulations considering the cavitation model to predict the power performance and to investigate the flow characteristics of the blade. The maximum power coefficient is shown to be about 47 under the condition where TSR = 7, and we observed cavitation on the suction and pressure sides of the blade.

Designing a Horizontal-Axis Wind Turbine for South Khorasan Province: A Case Study

Mehdi Jahangiri,Akbar Alidadi Shamsabadi 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.10

Climate change, population and economic growth, increasing fossil fuel prices and environmental issues together emphasize the generation of electricity through wind. The potential of wind for generating clean energy is remarkable in many parts of Iran. In this study, a statistical analysis was performed on wind data of Fadashk Station located in South Khorasan province in north east of Iran. Accordingly, a horizontal-axis wind turbine (HAWT) was designed for this station. Wind speed was studied in deferent months of the year at 10 m, 30 m and 40 m heights. In the mentioned heights, this station had a mean speed of 5.27, 6.20, and 6.33 m/s, respectively. Direction of the prevailing wind is almost fixed throughout the year and blows from southeast. Power density was obtained by estimating the potential of wind energy using Weibull probability distribution function. Furthermore, the amount of energy that could be obtained annually from this site was calculated by selecting two wind turbines, Kuriant18 turbine made by Kuriant Company and Vestas55 made by Vestas Company, in the actual state. Also, annual mean wind power density in this station was estimated 285 W/m2.

A comparison of the performance characteristics of large 2 MW and 3 MW wind turbines on existing onshore wind farms

Mehmet Bilgili,Firat Ekinci,Tugce Demirdelen 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.32 No.2

The aim of the current study is to compare the performance of large 2 MW and 3 MW wind turbines operating on existing onshore wind farms using Blade Element Momentum (BEM) theory and Angular Momentum (AM) theory and illustrate the performance characteristic curves of the turbines as a function of wind speed (U∞). To achieve this, the measurement data obtained from two different Wind Energy Power Plants (WEPPs) located in the Hatay region of Turkey was used. Two different horizontal-axis wind turbines with capacities of 2 MW and 3 MW were selected for evaluation and comparison. The hub-height wind speed (UD), turbine power output (P), atmospheric air temperature (Tatm) and turbine rotational speed (Ω) data were used in the evaluation of the turbine performance characteristics. Curves of turbine power output (P), axial flow induction factor (a), turbine rotational speed (Ω), turbine power coefficient (CP), blade tip speed ratio (λ), thrust force coefficient (CT) and thrust force (T) as a function of U∞ were obtained for the 2 MW and 3 MW wind turbines and these characteristic curves were compared. Results revealed that, for the same wind speed conditions, the higher-capacity wind turbine (3 MW) was operating at higher turbine power coefficient rates, while rotating at lower rotational speed ratios than the lower-capacity wind turbine (2 MW).

운전정지 조건에서 5 MW 수평축 풍력터빈 로터의 풍하중 해석

유기완,서윤호 한국풍공학회 2018 한국풍공학회지 Vol.22 No.4

본 연구에서는 운전 정지 상태로 회전하지 않는 수평축 해상 풍력터빈 로터에서 발생하는 풍하중을 풍속, 요 각도, 방위각, 피치 각도를 달리하면서 대기경계층 내에서 작동하는 조건으로 평가하였다. 하중 예측 결과의 검증을 위해 단순화 한 블레이드 형상에대한 블레이드 요소이론과 단순 계산치를 이용하여 얻어낸 공력 하중을 상호 비교하였으며, 코드와 비틀림 각도가 블레이드 스팬 방향에 따라 변하는 NREL 5 MW급 대형풍력터빈 로터에 대해서는 NREL에서 개발한 FAST 해석 결과와 본 연구의 해석 결과를 비교함으로써 해석 결과의 정확도를 검증하였다. 로터의 하중은 허브 중심을 원점으로 하는 고정된 3축 좌표계에 대해서 힘과 모멘트로 표현되는 6분력 하중으로 나타내었다. 따라서 이 결과는 풍력터빈 시스템의 동적 거동 해석과 로터에서 발생되는 전도 모멘트를 견디기위해 필요한 지지 구조물의 기초하중 자료로 적용할 수 있다. In this study, wind loads exerted on the offshore wind turbine rotor in parked condition were predicted with variations of wind speeds, yaw angles, azimuth angle, pitch angles, and power of the atmospheric boundary layer profile. The calculated wind loads using blade element theorem were compared with those of estimated aerodynamic loads for the simplified blade shape. Wind loads for an NREL’s 5 MW scaled offshore wind turbine rotor were also compared with those of NREL’s FAST results for more verification. All of the 6-component wind loads including forces and moments along the three axis were represented on a non-rotating coordinate system fixed at the apex of rotor hub. The calculated wind loads are applicable for the dynamic analysis of the wind turbine system, or obtaining the over-turning moment at the foundation of support structure for wind turbine system.

근사 원방 경계조건을 이용한 HAWT의 Navier-Stokes 유동해석

이철(Chul Lee),조창열(Chang-Yeol Joh) 한국항공우주학회 2008 韓國航空宇宙學會誌 Vol.36 No.6

Srinivasan 등이 제안한 용출-흡입 개념과 단순 운동량 이론을 응용한 근사 원방경계조건을 수평축 풍력터빈의 Navier-Stokes 유동장 해석에 적용하였다. 자연풍이 있는 풍력터빈에 대해서 반복적으로 근사 원방 경계조건을 적용하여 수치해를 구하였다. 원방경계 크기를 달리하여 근사 원방경계조건을 적용함으로써 수치해의 정확도 개선과 계산의 효율성을 분석하였다. 그 결과 본 경계조건의 적용은 전반적으로 해의 정확성을 개선시키며 원방경계의 크기가 작을수록 정확도의 개선효과는 증가하고 따라서 해석영역이 감소되어 계산 효율성이 증대된다. An approximate far-field boundary condition utilizing a source-sink idea for the rotor and the simple momentum theory were applied to the Navier-Stokes flow analysis around a horizontal-axis wind turbine. An iterative procedure was set up to apply this boundary condition to the flow with natural wind. Through computational tests for various distances of far-boundary, it was found that applying the approximate far-field boundary condition generally improves the accuracy of numerical solutions and computational efficiency. The solution becomes more accurate as the approximate boundary condition was applied to smaller far-field boundary.

비선형 와류법 개발 및 수평축 풍력터빈의 비정상 공력특성에 대한 수치적 연구

이학진(Hakjin Lee),조영민(Yeongmin Jo),이덕주(Duck-Joo Lee) 한국항공우주학회 2017 한국항공우주학회 학술발표회 논문집 Vol.2017 No.11