수직축 풍력터빈에 대한 유동과 모드 해석의 기초연구

하윤진(Yoon-Jin Ha),이영길(Young-Gill Lee),정광열(Kwang-Leol Jeong),조민태(Min-Tae Cho),강대선(Dae-Sun Kang) 한국해양환경·에너지학회 2012 한국해양환경공학회 학술대회논문집 Vol.2012 No.5

In this study, the flow characteristics around a vertical-axis wind turbine(VAWT) are investigated by numerical simulations. A vertical-axis wind turbine among existing articles is used as the objective model in the present research. The results of the numerical simulations are compared with the results of the model tests from published articles. Also, a plate is installed on the bottom of the vertical-axis wind turbine and found out about the influences of ike bottom plate. By the bottom plate, the tip vortices are reduced and the fiow characteristics are changed. The power coefficient of the wind turbine with bottom plate is increased by a maximum of 50%. Sizes of the wind turbine are deterntined for 1 kW power generation, and the sizes of them are compared with the other sizes of existing 1 AW class vertical-axis mind turbines. The projected area of the 1 kW wind turbine with bottom plate is reduced by a maximum of 30%. On the other hand, modd analyses are performed to find out the natural frequencies of the 1 kW wind turbine, and the resonance safety of the 1 kW wind turbine is estimated by the results of the modal analyses. The results of the present research could be used as one of the fundamental data to design a 1 kW class vertical-axis wind turbine.

Aerodynamic analysis and control mechanism design of cycloidal wind turbine adopting active control of blade motion

In Seong Hwang,Yun Han Lee,Seung Jo Kim 한국항공우주학회 2007 International Journal of Aeronautical and Space Sc Vol.8 No.2

This paper describes the cycloidal wind turbine, which is a straight blade vertical axis wind turbine using the cycloidal blade system. Cycloidal blade system consists of several blades rotating about an axis in parallel direction. Each blade changes its pitch angle periodically. Cycloidal wind turbine is different from the previous turbines. The wind turbine operates with optimum rotating forces through active control of the blade to change pitch angle and phase angle according to the changes of wind direction and wind speed. Various numerical experiments were conducted to develop a small vertical axis wind turbine of 1 ㎾ class. For this numerical analysis, the rotor system equips four blades consisting of a symmetric airfoil NACA0018 of 1.0 m in span, 0.22 m in chord and 1.0 m in radius. A general purpose commercial CFD program, STAR-CD, was used for numerical analysis. PCL of MSC/PATRAN was used for efficient parametric auto mesh generation. Variables of wind speed, pitch angle, phase angle and rotating speed were set in the numerical experiments. The generated power was obtained according to the various combinations of these variables. Optimal pitch angle and phase angle of cycloidal blade system were obtained according to the change of the wind direction and the wind speed. Based on data obtained from the above analysis, control device was designed. The wind direction and the wind speed were sensed by a wind indicator and an anemometer. Each blades were actuated to optimal performance values by servo motors.

Aerodynamic analysis and control mechanism design of cycloidal wind turbine adopting active control of blade motion

Hwang, In-Seong,Lee, Yun-Han,Kim, Seung-Jo 한국항공우주학회 2007 International Journal of Aeronautical and Space Sc Vol.7 No.2

This paper describes the cycloidal wind turbine, which is a straight blade vertical axis wind turbine using the cycloidal blade system. Cycloidal blade system consists of several blades rotating about an axis in parallel direction. Each blade changes its pitch angle periodically. Cycloidal wind turbine is different from the previous turbines. The wind turbine operates with optimum rotating forces through active control of the blade to change pitch angle and phase angle according to the changes of wind direction and wind speed. Various numerical experiments were conducted to develop a small vertical axis wind turbine of 1 kW class. For this numerical analysis, the rotor system equips four blades consisting of a symmetric airfoil NACA0018 of 1.0m in span, 0.22m in chord and 1.0m in radius. A general purpose commercial CFD program, STAR-CD, was used for numerical analysis. PCL of MSC/PATRAN was used for efficient parametric auto mesh generation. Variables of wind speed, pitch angle, phase angle and rotating speed were set in the numerical experiments. The generated power was obtained according to the various combinations of these variables. Optimal pitch angle and phase angle of cycloidal blade system were obtained according to the change of the wind direction and the wind speed. Based on data obtained from the above analysis, control device was designed. The wind direction and the wind speed were sensed by a wind indicator and an anemometer. Each blades were actuated to optimal performance values by servo motors.

수직축 풍력터빈의 기동특성에 관한 수치해석

정호윤(Ho-Yun Jung),이연원(Yeon-Won Lee),김영덕(Young-Duk Kim) 한국마린엔지니어링학회 2008 한국마린엔지니어링학회 학술대회 논문집 Vol.2008 No.-

The wind turbine system is divided by two types. One is horizontal axis wind turbine and the other is vertical axis wind turbine. Typical types of vertical wind turbine are Darrieus type and Savonius type, etc. The Darrieus type is driven by lift force and Savonius type is driven by drag force. The objective of this study is to investigate the aerodynamic characteristics of a new type vertical axis wind turbine blade as the basic study of a design of a vertical axis wind turbine and to estimate the efficiency of wind turbine.

수직축 풍력터빈의 기동특성에 관한 수치해석

정호윤(Ho-Yun Jung),이연원(Yeon-Won Lee),김영덕(Young-Duk Kim) 한국항해항만학회 2008 한국항해항만학회 학술대회논문집 Vol.2008 No.공동학술

The wind turbine system is divided by two types. One is horizontal axis wind turbine and the other is vertical axis wind turbine. Typical types of vertical wind turbine are Darrieus type and Savonius type, etc. The Darrieus type is driven by lift force and Savonius type is driven by drag force. The objective of this study is to investigate the aerodynamic characteristics of a new type vertical axis wind turbine blade as the basic study of a design of a vertical axis wind turbine and to estimate the efficiency of wind turbine.

Blockage corrections for wind tunnel tests conducted on a Darrieus wind turbine

Jeong, Houigab,Lee, Seungho,Kwon, Soon-Duck Elsevier 2018 Journal of wind engineering and industrial aerodyn Vol.179 No.-

<P><B>Abstract</B></P> <P>In this study, the influence of the blockage ratio in three wind tunnel tests conducted on a small vertical-axis Darrieus wind turbine was quantitatively investigated. The vertical-axis Darrieus wind turbine was installed in three wind tunnels with different test-section sizes corresponding to blockage ratios of 3.5, 13.4, and 24.7%. The rotor torques, drag force, and upstream wind speeds were measured for the different blockage ratios. It is recommended from the tests that the reference wind speed of the wind turbine should be measured upstream at a distance of 3.5 times or more than the turbine diameter. The power coefficient of the wind turbine was severely distorted based on the blockage ratio. The power coefficients at blockage ratios of 13.4 and 24.7% were respectively 1.3 and 2 times higher than that at a blockage ratio of 3.5%. The optimal tip speed ratio also significantly shifted to a higher range. Based on the method proposed by Maskell (1963), a new correction coefficient is proposed for the Darrieus turbine from the measured drag coefficients obtained at three different blockage ratios. The validity of the proposed correction coefficient was confirmed by comparing it with the corrected power coefficients obtained using other correction methods.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A Darrieus vertical-axis wind turbine was tested in three different wind tunnels with different blockage ratios. </LI> <LI> New correction method for blockage effect is proposed for a Darrieus turbine based on the measurements. </LI> <LI> The present method corrects not only the maximum power coefficient but also the optimal tip speed ratio. </LI> </UL> </P>

수직축 풍력터빈의 후류 특성에 관한 실험적 연구

정회갑,이승호,권순덕 한국풍력에너지학회 2017 풍력에너지저널 Vol.8 No.1

A study of far wake characteristic of vertical wind turbines is necessary in order to sit them on a wind farm array. Most research has been conducted on flow measurements of near-wake in a vertical wind turbine, but very limited studies are found in far wake model. This study presents quantitative results of wind tunnel tests for far wake field of a Darrieus vertical axis wind turbine. Hot-wire anemometry was used to measure the distribution of mean velocity deficits and turbulence intensities, positioning it behind in distances between 2 and 12 times the diameter of the rotor. In comparison with horizontal axis wind turbine, velocity deficit and wake width of vertical axis wind turbines showed similar trend, and they set apart in two notable characteristics: drift of the lower peak velocity location and acceleration of wind velocity near the rotor.

Computational study of a small scale vertical axis wind turbine (VAWT): comparative performance of various turbulence models

Aresti, Lazaros,Tutar, Mustafa,Chen, Yong,Calay, Rajnish K. Techno-Press 2013 Wind and Structures, An International Journal (WAS Vol.17 No.6

The paper presents a numerical approach to study of fluid flow characteristics and to predict performance of wind turbines. The numerical model is based on Finite-volume method (FVM) discretization of unsteady Reynolds-averaged Navier-Stokes (URANS) equations. The movement of turbine blades is modeled using moving mesh technique. The turbulence is modeled using commonly used turbulence models: Renormalization Group (RNG) k-${\varepsilon}$ turbulence model and the standard k-${\varepsilon}$ and k-${\omega}$ turbulence models. The model is validated with the experimental data over a large range of tip-speed to wind ratio (TSR) and blade pitch angles. In order to demonstrate the use of numerical method as a tool for designing wind turbines, two dimensional (2-D) and three-dimensional (3-D) simulations are carried out to study the flow through a small scale Darrieus type H-rotor Vertical Axis Wind Turbine (VAWT). The flows predictions are used to determine the performance of the turbine. The turbine consists of 3-symmetrical NACA0022 blades. A number of simulations are performed for a range of approaching angles and wind speeds. This numerical study highlights the concerns with the self-starting capabilities of the present VAWT turbine. However results also indicate that self-starting capabilities of the turbine can be increased when the mounted angle of attack of the blades is increased. The 2-D simulations using the presented model can successfully be used at preliminary stage of turbine design to compare performance of the turbine for different design and operating parameters, whereas 3-D studies are preferred for the final design.

그린전력을 생산하는 도시형 소형 풍력발전

윤희중 한국물리학회 2016 새물리 Vol.66 No.9

In general, the wind industry has been oriented toward large power systems that require large windy areas and that because of environmental restrictions, should be constructed in regions far away from residential districts. However, recently, small-scale wind generation has moved closer to consumers and now has potential for applications to urban wind power generation with more silent wind turbines. The basic condition for harvesting wind power successfully is, of course, the ability of wind: Hence, an accurate prediction of the wind speed is essential for calculating the electricity output of small wind generators because the output is the basis for its economic performance. In this paper, we review the extent of available data and the progress that has taken place in analysis techniques and tools for determining the wind conditions in urban areas and predict the possibility of applications for the green power generation with small-scale wind turbines. We have paraphrased the hydrodynamic analysis and torque diagrams so citizen might have easy access to green power system. 일반적으로 풍력발전은 날개의 회전면적이 큰 대형풍력발전을 말하며 주위 환경에 신경을 쓰지 않는 주거지역과 멀리 떨어진 지역에 설치되는 발전시설을 말한다. 그러나 최근에는 미풍에도 기동되고 조용하게 운용되는 소형풍력터빈이 개발됨으로 도시지역의 그린전력 생산에 적용할 수 있는 소형풍력 발전 시스템의 적용범위가 확대되고 있다. 풍력발전을 위해서는 설치장소에서 풍속을 정확하게 예측하는 것이 필수적이다. 이를 기반으로 효율성과 경제성을 판단하기 때문이다. 이 논문에서는 도시지역에서 풍력자원과 터빈기술을 효율적으로 활용함으로써 도시지역에서 그린전력 생산가능성을 분석하고 전망한다. 특히 도시지역의 복잡한 풍황조건을 이해하고 분석하는데 필요한 기초적인 유체동역학적 거동과 블레이드가 받는 토크의 벡터연산과정을 도식화하여 일반국민들이 그린전력생산시스템에 쉽게 접근할 수 있게 부연하였다.

Simple vibration model for the design of a vertical axis wind turbine

Hyung Hee Kim,Yutaek Oh,Hong Hee Yoo 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.2

Wind turbines are widely used these days as one of renewable energy sources. In this paper, a dynamic model of a vertical axis wind turbine is developed by considering coupling effects among shaft bending, shaft torsion, shaft tension, rotor tension and rotor bending. The modal characteristics of the vertical axis wind turbine were obtained by using the dynamic model. The accuracy of the proposed model was first validated by comparing its numerical results to those obtained with a commercial program. Then, the effects of key design parameters such as shaft length, shaft diameter and rotor cross section area on the modal characteristics of the wind turbine were investigated. The natural frequency loci veering phenomena occurred when those parameters varied. The loci veering phenomena were associated with the mode shape switch between shaft bending and rotor bending, which should be carefully examined to improve the vibration quality of the wind turbine. The main contribution of this study is to propose a simple vibration model by which the effects of various design parameters on the modal characteristics of the vertical axis wind turbine can be investigated. Some design guidelines related to the vibration performance are also suggested.