• Proceedings of the KIPE Conference
• /
• 2010.11a
• /
• pp.250-251
• /
• 2010

본 연구는 수평축(horizontal axis) 풍력 터빈에 의해서 수직축 발전기를 운전하는 구조 및 그 운전 방식에 관한 것으로서 바람에 의해 수평축 터빈 로터로 입력된 회전력을 기계적으로 두 개의 수직축 회전 성분으로 변환하여 이들로부터 전기 에너지를 얻어내고 필요에 따라 터빈 날개가 바람이 부는 방향을 향하도록 yaw-axis 제어를 하는 기술에 관한 것이다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.677-681
• /
• 2011

Characteristics of vertical and horizontal axis wind turbines are explained. The speed and direction of wind on the blade of the Darrieus type turbine changes very severely. Therefore dynamic stall happens periodically and the wake from the front blade deteriorates the performance of rear blades. Blade element momentum theory(BEMT) is widely utilized for aerodynamic design and performace prediction of horizontal axis wind turbine(HAWT). Computation analysis and wind tunnel test are also performed for the performance prediction.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.182.1-182.1
• /
• 2010

현재 전 세계적으로 가장 널리 개발하고 보급되어지고 있는 풍력산업의 시장 규모는 매년 확대되고 있다. 특히 소형 풍력발전 시스템은 낙도 등의 전력 공급이 어려운 지역에 경제성 있는 전력 보급을 가능하게 한다. 국내의 미전화 지역과 일반 가정에서 풍력 에너지 자원을 적극 활용 개발하기 위해서 보다 우수한 성능의 풍력발전기용 블레이드를 설계하고자, 공기역학적인 최적설계에 대해 연구함으로써 추후 보급형 풍력발전 시스템의 개발에 필요한 설계 기술을 확립하고자한다. 본 연구는 설계된 블레이드의 유동해석 및 성능예측을 위하여 경제적으로 많은 지원이 필요한 대규모 풍동실험이 아닌 상용 CFD를 사용하여 보다 효율적으로 우수한 성능을 가지는 풍력 터빈을 설계함에 있다. Reynolds Averaged Navier-Stokes 방정식에 기반을 둔 CFD의 경우 이론적으로 명확한 해석이 가능하고, 실제 터빈의 운전 환경과 동일한 다양한 물리적 변수를 입력 데이터로서 활용할 수 있는 장점이 있기 때문에 풍력 터빈의 설계 과정에서 반영된 미소한 블레이드 형상변화 및 운전 조건의 변화에 따른 유동장의 변화 및 풍력터빈 성능을 정확히 예측할 수 있는 장점을 가지고 있다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.5
• /
• pp.391-398
• /
• 2016

This study focused on the aerodynamic loads of the horizontal axis wind turbine blade due to the normal turbulence inflow condition. Normal turbulence model (NTM) includes the variations of wind speed and direction, and it is characterized by turbulence intensity and standard deviation of flow fluctuation. IEC61400-1 recommends the fatigue analysis for the NTM and the normal wind profile (NWP) conditions. The aerodynamic loads are obtained at the blade hub and the low speed drive shaft for MW class horizontal axis wind turbine which is designed by using aerodynamically optimized procedure. The 6-components of aerodynamic loads are investigated between numerical results and load components analysis. From the calculated results the maximum amplitudes of oscillated thrust and torque for LSS with turbulent inflow condition are about 5~8 times larger than those with no turbulent inflow condition. It turns out that the aerodynamic load analysis with normal turbulence model is essential for structural design of the wind turbine blade.

• Journal of the wind engineering institute of Korea
• /
• v.22 no.4
• /
• pp.163-169
• /
• 2018

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.

• Journal of Wind Energy
• /
• v.2 no.1
• /
• pp.61-67
• /
• 2011

In the present study, numerical unsteady simulations of the NREL Phase VI wind turbine in downwind operation conditions were conducted to investigate rotor-tower interaction. The calculations were performed using an unstructured mesh, incompressible Reynolds-averaged Navier-Stokes flow solver. To capture the unsteady effects associated with the tower shadow between the rotor blades and the tower, the wind turbine was modelled including the rotor, tower, hub, and nacelle. The present results generally showed good agreements with available experimental data. At the lowest wind speed, the pressure distribution was characterized by a complete collapse of the suction peak on the blade when the blade passes through the tower wake. It was found that unsteady effects play a significant role in the response of the blades.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.8
• /
• pp.1170-1179
• /
• 2009

The purpose of this work is to predict the low frequency aero-acoustic noise generated from the horizontal axis wind turbine, NREL Phase VI for the whole operating conditions of various wind speeds using large eddy simulation and Ffowcs-Williams and Hawkings model provided in the commercial code, FLUENT. Because there is no experimental data about wind turbine noise, we first of all compared aerodynamic performance such as shaft torque and power with experimentally measured value. Performance results show a good agreement with experimental data within about 0.8%. As the wind speed increases, the overall sound pressure level and the sound pressure level by the quadrupole and dipole source show a increasing tendency. Also, sound pressure level is proportional to $r^{-2}$ in the near field and $r^{-1}$ in the far field according to the increase of distance from the center of hub of wind turbine. According to 2 times increase of distance, sound pressure level is reduced by about 6dB.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.10
• /
• pp.884-890
• /
• 2007

The procedure for the aerodynamic design of the rotor blades for 10 kW-level HAWT (horizontal axis wind turbine) has been investigated to be practiced systematically. The approximately optimal shape was designed using an inverse method based on the momentum theory and the blade element method. The configuration was tested in the wind tunnel of the Korea Air Force Academy, and the data was compared with those obtained from the real system manufactured from the present design. From this research, the authors established the systematic technolo for wind turbine blades, and set up the technical procedure which can be extended for the future design of middle and large sized wind turbines.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.47-50
• /
• 2005

본 연구의 목적은 차세대 대체에너지로 각광받는 풍력발전 중에서 육상발전보다 여러 가지 이점이 있는 해상에서의 한국형 풍력터빈 블레이드의 최적 형상을 위 한 알고리즘을 구현하는 것이다. 풍력터빈 블레이드에서 깃익형의 공기 역학적 특성은 매우 중요한 사항이다. 이를 위해서 익형 성능예측에 층류에서 난류로의 천이과정을 포함하는 XFOIL을 이용하여 블레이드 익형 단면의 양력과 항력 분포를 해석하였다. 첫 번째 수준의 설계변수는 운용범위내의 바람의 속도와 블레이드 지름, 축 회전수이며, 각 단면에서의 비틀림각과 시위길이는 두 번째 수준의 설계 변수이다. 운용범위 내의 각 설계점에서 익형의 공력 변수들과 최소에 너지손실 조건을 이용하여 시위길이와 피치각 분포를 최적화하였다. 각각의 설계점에서 결과를 바탕으로 풍력발전의 설계 운용범위에서 반응면을 구성하고 구배최적화 기법을 통해 요구동력의 제약함수를 만족하고 효율을 최대로 하는 블레이드 형상을 구현하였다. 최적형상에 대해 탈설계점 해석을 수행하여 그 성능을 구하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.11
• /
• pp.964-972
• /
• 2007

Wind turbine experiment was carried out for the horizontal axis wind turbine with the aerodynamically optimized blade. From the comparison of aerodynamic performance between upwind and downwind type wind turbine rotor, the measured torque fluctuation of the latter is larger than that of the former. This phenomenon is owing to the interaction of wake generated from support column and blades. The wind turbine model satisfies the design condition in that the measured result of the power coefficient at zero pitch angle shows maximum peak at the designed tip speed ratio, λ = 6. It also shows that the decrease in aerodynamic power due to negative pitch change is more sensitive than that of the same positive pitch change.