Strategic Blade Shape Optimization for Aerodynamic Performance Improvement of Wind Turbines

2016 ◽  
Author(s):  
Youjin Kim ◽  
Ali Al-Abadi ◽  
Antonio Delgado
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Optimization Methods ◽  
Turbine Rotor ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Blade Shape ◽  
Improved Design ◽  
Wind Turbine Rotor

This study introduces strategic methods for improving the aerodynamic performance of wind turbines. It was completed by combining different optimization methods for each part of the wind turbine rotor. The chord length and pitch angle are optimized by a torque-matched method (TMASO), whereas the airfoil shape is optimized by the genetic algorithm (GA). The TMASO is implemented to produce an improved design of a reference turbine (NREL UAE Phase V). The GA is operated to generate a novel airfoil design that is evaluated by automatic interfacing for the highest gliding ratio (GR). The adopted method produces an optimized wind turbine with an 11% increase of power coefficient (Cp) with 30% less of the corresponding tip speed ratio (TSR). Furthermore, the optimized wind turbine shows reduced tip loss effect.

Development of a Scaled Rotor Blade for Tank Tests of Floating Wind Turbine Systems

2018 ◽  
Author(s):  
Paul Schünemann ◽  
Timo Zwisele ◽  
Frank Adam ◽  
Uwe Ritschel
Keyword(s):  
Wind Turbine ◽  
Rotor Blade ◽  
Turbine Rotor ◽  
Full Scale ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Model Scale ◽  
Floating Wind Turbine ◽  
Hydrodynamic Effects ◽  
Wind Turbine Rotor

Floating wind turbine systems will play an important role for a sustainable energy supply in the future. The dynamic behavior of such systems is governed by strong couplings of aerodynamic, structural mechanic and hydrodynamic effects. To examine these effects scaled tank tests are an inevitable part of the design process of floating wind turbine systems. Normally Froude scaling is used in tank tests. However, using Froude scaling also for the wind turbine rotor will lead to wrong aerodynamic loads compared to the full-scale turbine. Therefore the paper provides a detailed description of designing a modified scaled rotor blade mitigating this problem. Thereby a focus is set on preserving the tip speed ratio of the full scale turbine, keeping the thrust force behavior of the full scale rotor also in model scale and additionally maintaining the power coefficient between full scale and model scale. This is achieved by completely redesigning the original blade using a different airfoil. All steps of this redesign process are explained using the example of the generic DOWEC 6MW wind turbine. Calculations of aerodynamic coefficients are done with the software tools XFoil and AirfoilPrep and the resulting thrust and power coefficients are obtained by running several simulations with the software AeroDyn.

scholarly journals Pengaruh Jumlah Bilah dan Sudut Pasang terhadap Daya Turbin Angin Poros Vertikal Tipe H-Darrieus Termodifikasi sebagai Energi Alternatif Pembangkit Tenaga Listrik Skala Rumah Tangga

2019 ◽  
Vol 12 (2) ◽  
pp. 92
Author(s):  
Susilo Susilo ◽  
Bambang Widodo ◽  
Eva Magdalena Silalahi ◽  
Atmadi Priyono
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Output Power ◽  
Wind Turbines ◽  
Output Voltage ◽  
Turbine Rotor ◽  
Wind Speeds ◽  
Blade Shape ◽  
Low Wind Speeds ◽  
Wind Turbine Rotor

Bentuk sudu taper linier merupakan bentuk sudu yang paling optimal untuk kecepatan angin yang rendah. Jumlah sudu yang baik untuk kecepatan angin rendah berkisar antara 3-7 buah sudu, namun desain sudu dengan menggunakan airfoil dan profil pada sudut pasang sudu yang bagaimana memberikan daya keluaran dan tegangan keluaran yang optimal. Turbin angin didesain dengan 2 bilah dan 4 bilah dengan sudut pasang yang bisa diatur untuk mendapatkan perbedaan daya optimal masing-masing desain. Pengujian dilakukan di 3 area berbeda untuk mendapatkan gambaran geografis kondisi angin yang berbeda khususnya masalah kecepatan angin di ksiaran 2 m/s - 7 m/s. Pengujian dilakukan dengan luas penampang turbin angin (A) sebesar 3m2 Hasil penelitian menunjukkan bahwa nilai terbaik diperoleh pada kecepatan angin maksimal 4 m/s dan jumlah blade 4  sedangkan untuk nilai terkecil diperoleh pada kecepatan angin 3 m/s dan jumlah blade 2 yaitu. Untuk nilai TSR maksimal pada kecepatan maksimal 4 m/s terjadi pada jumlah blade 4, sedangkan untuk nilai terendah pada kecepatan angin 3 m/s dihasilkan pada jumlah blade 2. Melalui pengukuran berbasis teknologi smart monitoring system, dari penelitian diperoleh semakin tinggi kecepatan angin maka tegangan keluaran semakin tinggi. Semakin tinggi tegangan keluaran, semakin tinggi daya keluaran pada generator. Sudut pasang ? dan jumlah sudu mempengaruhi kecepatan putaran rotor turbin angin. Kecepatan putaran rotor turbin angin berelasi dengan tegangan keluaran generator. pada sudut pasang ? dan jumlah sudu 4, diperoleh daya keluaran yang sebesar 150 watt namun pada kecepatan angin 7 m/s daya turbin yang dihasilkan mencapai 600 watt. Dengan kondisi ini cukup memenuhi untuk alternatif cadangan listrik skala rumah tangga khusunya di pedesaan dan daerah terpencil (rural area). The linear taper blade shape is the most optimal blade shape for low wind speeds. The number of blades that are good for low wind speeds ranges from 3-7 blades, but the blade design uses an airfoil and profile on the blade mounting angle which is how to provide optimal output power and output voltage. Wind turbines are designed with 2 blades and 4 blades with adjustable tide angles to get the difference in the optimal power of each design. Tests were carried out in 3 different areas to obtain a geographical description of different wind conditions, especially the problem of wind speed in the range of 2 m / s - 7 m / s. Tests carried out with a cross section area of  wind turbines (A) of 3m2 The results showed that the best value was obtained at a maximum wind speed of 4 m / s and number 4 blade while the smallest value was obtained at wind speeds of 3 m / s and number 2 blades namely. For the maximum TSR value at a maximum speed of 4 m / s occurs in the number of 4 blades, while for the lowest value at 3 m / s wind speed is produced on the number of blades 2. From the research, the higher the wind speed, the higher the output voltage. The higher the output voltage, the higher the output power at the generator. The ? tide angle and number of blades affect the speed of the wind turbine rotor rotation. The rotational speed of the wind turbine rotor is related to the generator output voltage. at the tide angle ? and number of blades 4, the output power of 150 watts is obtained but with wind speed 7 m/s turbine power 600 watt achieved. With this condition, it is sufficient for alternative household electricity reserves, especially in rural and remote areas (rural areas).

scholarly journals Effects of Inflow Shear on Wake Characteristics of Wind-Turbines over Flat Terrain

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3745 ◽  
Author(s):  
Takanori Uchida
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Turbine Rotor ◽  
Wind Tunnel Experiment ◽  
Scale Model ◽  
Speed Ratio ◽  
Flat Terrain ◽  
Wind Turbine Rotor ◽  
Wake Characteristics

The scope of the present study was to understand the wake characteristics of wind-turbines under various inflow shears. First, in order to verify the prediction accuracy of the in-house large-eddy simulation (LES) solver, called RIAM-COMPACT, based on a Cartesian staggered grid, we conducted a wind-tunnel experiment using a wind-turbine scale model and compared the numerical and experimental results. The total number of grid points in the computational domain was about 235 million. Parallel computation based on a hybrid LES/actuator line (AL) model approach was performed with a new SX-Aurora TSUBASA vector supercomputer. The comparison between wind-tunnel experiment and high-resolution LES results showed that the AL model implemented in the in-house LES solver in this study could accurately reproduce both performances of the wind-turbine scale model and flow characteristics in the wake region. Next, with the LES solver developed in-house, flow past the entire wind-turbine, including the nacelle and the tower, was simulated for a tip-speed ratio (TSR) of 4, the optimal TSR. Three types of inflow shear, N = 4, N = 10, and uniform flow, were set at the inflow boundary. In these calculations, the calculation domain in the streamwise direction was very long, 30.0 D (D being the wind-turbine rotor diameter) from the center of the wind-turbine hub. Long-term integration of t = 0 to 400 R/Uin was performed. Various turbulence statistics were calculated at t = 200 to 400 R/Uin. Here, R is the wind-turbine rotor radius, and Uin is the wind speed at the hub-center height. On the basis of the obtained results, we numerically investigated the effects of inflow shear on the wake characteristics of wind-turbines over a flat terrain. Focusing on the center of the wind-turbine hub, all results showed almost the same behavior regardless of the difference in the three types of inflow shear.

Four Decades of Research Into the Augmentation Techniques of Savonius Wind Turbine Rotor

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Nur Alom ◽  
Ujjwal K. Saha
Keyword(s):  
Wind Turbine ◽  
Turbine Rotor ◽  
Power Coefficient ◽  
Major Drawback ◽  
High Rotational Speed ◽  
Savonius Rotor ◽  
Augmentation Techniques ◽  
Savonius Wind Turbine ◽  
Low Efficiency ◽  
Wind Turbine Rotor

The design and development of wind turbines is increasing throughout the world to offer electricity without paying much to the global warming. The Savonius wind turbine rotor, or simply the Savonius rotor, is a drag-based device that has a relatively low efficiency. A high negative torque produced by the returning blade is a major drawback of this rotor. Despite having a low efficiency, its design simplicity, low cost, easy installation, good starting ability, relatively low operating speed, and independency to wind direction are its main rewards. With the goal of improving its power coefficient (CP), a considerable amount of investigation has been reported in the past few decades, where various design modifications are made by altering the influencing parameters. Concurrently, various augmentation techniques have also been used to improve the rotor performance. Such augmenters reduce the negative torque and improve the self-starting capability while maintaining a high rotational speed of the rotor. The CP of the conventional Savonius rotors lie in the range of 0.12–0.18, however, with the use of augmenters, it can reach up to 0.52 with added design complexity. This paper attempts to give an overview of the various augmentation techniques used in Savonius rotor over the last four decades. Some of the key findings with the use of these techniques have been addressed and makes an attempt to highlight the future direction of research.

Numerical Analysis of a Rooftop Vertical Axis Wind Turbine

2011 ◽  
Author(s):  
N. Cristobal Uzarraga-Rodriguez ◽  
A. Gallegos-Mun˜oz ◽  
J. Manuel Riesco A´vila
Keyword(s):  
Numerical Analysis ◽  
Wind Turbine ◽  
Numerical Study ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Sliding Mesh ◽  
Mesh Model

A numerical analysis of a rooftop vertical axis wind turbine (VAWT) for applications in urban area is presented. The numerical simulations were developed to study the flow field through the turbine rotor to analyze the aerodynamic performance characteristics of the device. Three different blade numbers of wind turbine are studied, 2, 3 and 4, respectively. Each one of the models was built in a 3D computational model. The effects generated in the performance of turbines by the numbers of blades are considered. A Sliding Mesh Model (SMM) capability was used to present the dimensionless form of coefficient power and coefficient moment of the wind turbine as a function of the wind velocity and the rotor rotational speed. The numerical study was developed in CFD using FLUENT®. The results show the aerodynamic performance for each configuration of wind turbine rotor. In the cases of Rooftop rotor the power coefficient increases as the blade number increases, while in the case of Savonius rotor the power coefficient decrease as the blades number increases.

The Rotor Speed Control of 5MW Wind Turbine under Rated Wind Speed Using Adaptive-PID Controller

2012 ◽  
Vol 229-231 ◽  
pp. 2323-2326
Author(s):  
Zong Qi Tan ◽  
Can Can Li ◽  
Hui Jun Ye ◽  
Yu Qiong Zhou ◽  
Hua Ling Zhu
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Pid Controller ◽  
Turbine Rotor ◽  
Speed Ratio ◽  
Rotor Speed ◽  
Rotating Speed ◽  
Tip Speed Ratio ◽  
Variable Wind ◽  
Wind Turbine Rotor

This paper designed the controller of the wind turbine rotor rotating speed. This model of adaptive-PID through control the tip-speed ratio and count the values of PID for variable wind speed. From the result of simulation, the wind speed can run in a good dynamic characteristic, and keep the rotor running in the best tip-speed ratio at the same time.

Design and Evaluation of a Rooftop Wind Turbine Rotor With Untwisted Blades

2013 ◽  
Author(s):  
Sayem Zafar ◽  
Mohamed Gadalla
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Low Cost ◽  
Turbine Blades ◽  
Angle Of Attack ◽  
Turbine Rotor ◽  
Wind Turbine Blades ◽  
Wind Speeds ◽  
Small Wind Turbines ◽  
Wind Turbine Rotor

A small horizontal axis wind turbine rotor was designed and tested with aerodynamically efficient, economical and easy to manufacture blades. Basic blade aerodynamic analysis was conducted using commercially available software. The blade span was constrained such that the complete wind turbine can be rooftop mountable with the envisioned wind turbine height of around 8 m. The blade was designed without any taper or twist to comply with the low cost and ease of manufacturing requirements. The aerodynamic analysis suggested laminar flow airfoils to be the most efficient airfoils for such use. Using NACA 63-418 airfoil, a rectangular blade geometry was selected with chord length of 0.27[m] and span of 1.52[m]. Glass reinforced plastic was used as the blade material for low cost and favorable strength to weight ratio with a skin thickness of 1[mm]. Because of the resultant velocity changes with respect to the blade span, while the blade is rotating, an optimal installed angle of attack was to be determined. The installed angle of attack was required to produce the highest possible rotation under usual wind speeds while start at relatively low speed. Tests were conducted at multiple wind speeds with blades mounted on free rotating shaft. The turbine was tested for three different installed angles and rotational speeds were recorded. The result showed increase in rotational speed with the increase in blade angle away from the free-stream velocity direction while the start-up speeds were found to be within close range of each other. At the optimal angle was found to be 22° from the plane of rotation. The results seem very promising for a low cost small wind turbine with no twist and taper in the blade. The tests established that non-twisted wind turbine blades, when used for rooftop small wind turbines, can generate useable electrical power for domestic consumption. It also established that, for small wind turbines, non-twisted, non-tapered blades provide an economical yet productive alternative to the existing complex wind turbine blades.

Prediction of Aerodynamic Noise Radiated From a Vertical-Axis Wind Turbine

2003 ◽  
Author(s):  
Akiyoshi Iida ◽  
Akisato Mizuno ◽  
Kyoji Kamemoto
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Sound Source ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Low Noise ◽  
Aerodynamic Noise ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine

Unsteady flow field and flow induced noise of vertical axis wind turbine are numerically investigated. The flow field is numerically calculated by the vortex method with core-spreading model. This simulation obtains aerodynamic performance and aerodynamic forces. Aerodynamic noise is also simulated by using Ffowcs Williams-Hawkings equation with compact body and low-Mach number assumptions. Tip speed of rotor blades are not so high, then the contribution of the moving sound source is smaller than that of the dipole sound source. Since the maximum power coefficient of VAWT can be obtained at lower tip-speed ratio compared to the conventional, horizontal axis wind turbines, the aerodynamic noise from vertical axis wind turbine is smaller than that of the conventional wind turbines at the same aerodynamic performance. This result indicates that the vertical axis wind turbines are useful to develop low-noise wind turbines.

Aerodynamic Design and Analysis of a Flanged Diffuser Augmented Wind Turbine

2013 ◽  
Author(s):  
A. Tourlidakis ◽  
K. Vafiadis ◽  
V. Andrianopoulos ◽  
I. Kalogeropoulos
Keyword(s):  
Wind Speed ◽  
Flow Field ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Research Work ◽  
Flow Analysis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Computational Domain ◽  
Aerodynamic Design

Many researchers proposed methods for improving the efficiency of small Horizontal Axis Wind Turbines (HAWTs). One of the methods developed to increase the efficiency of HAWTs and to overcome the theoretical Betz limit is the introduction of a converging – diverging casing around the turbine. To further improve the performance of the diffuser a flange is placed at its outlet, which smoothes the flow along the diffuser interior, allowing larger diffusion angles to be utilized. The purpose of this research work is the aerodynamic design and computational analysis of such an arrangement with the use of Computational Fluid Dynamics (CFD). First, a HAWT rotor rotating at 600 RPM was designed with the use of the Blade Element Momentum (BEM) method. The three rotor blades are constructed using the NREL airfoil sections family S833, S834 and S835. The power coefficient of the rotor was optimised in a wind speed range of 5 – 10 m/s, with a maximum value of 0.45 for a wind speed of 7m/s. A full three-dimensional CFD analysis was carried out for the modeling of the flow around the rotor and through the flanged diffuser. The computational domain consisted of two regions with different frames of reference (a stationary and a rotating). The rotating frame rotates at 600 RPM and includes the rotor with the blades. All the simulations were performed using the commercial CFD software package ANSYS CFX. The Shear Stress Transport turbulence model was used for the simulations. Detailed flow analysis results are presented, dealing with the various investigated test cases, a) isolated turbine rotor, b) diffuser without the presence of the turbine, and c) the full turbine – diffuser arrangement for different flange heights and wind speeds. By varying the height of the flange and the wind speed, the effects of the above on the flow field and the power coefficient of the turbine were studied. The CFD resulting power coefficients are also compared and good agreement with existing in the literature experimental data was obtained. The results showed that there is a significant improvement in the performance of the wind turbine (by a factor from 2 to 5 on power coefficient at high blade tip speed ratio) and the proposed modification is particularly attractive for small wind turbines. The particular characteristics of the flow field, that are responsible for this improvement are identified and analysed in detail offering a better understanding of the physical processes involved.

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