scholarly journals Design of an active pitch control for small horizontal-axis wind turbine

2021 ◽  
Vol 19 ◽  
pp. 195-198
Author(s):  
J. Vilà ◽  
◽  
N. Luo ◽  
L. Pacheco ◽  
T. Pujol ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Power Output ◽  
Low Cost ◽  
Small Scale ◽  
End User ◽  
Power Capacity ◽  
Horizontal Axis Wind Turbine ◽  
Pitch Control ◽  
Small Wind Turbines

The installed power capacity from small wind turbines would rise in case of having higher efficiency values. The performance of these devices is very sensitive to wind conditions, especially to wind gusts and turbulence. Performance extracted from small-scale wind turbine datasheets show large variations of power output between turbulent and non-turbulent sites and often the installation in intermittent wind sites is discouraged. The use of blades with fixed positions is a clear drawback of small wind turbines. Here, we propose a design of a smart active pitch control to increase the energy generation of micro-wind turbines (< 5 kWp). The design consists of a simple mechanism that allows the rotation of the blades controlled by a low cost peripheral interface controller. The possibility to orientate the blades so as to maximise the power output at all wind conditions will increase the performance of this small wind turbines. The design is robust and economical, which will increase its potential adoptability rate by the end-user.

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.

The Straight-Bladed Morphing Vertical Axis Wind Turbine

2016 ◽  
Author(s):  
David MacPhee ◽  
Asfaw Beyene
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Low Cost ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Pitch Control ◽  
Control Schemes ◽  
Horizontal Axis Wind Turbines ◽  
Novel Concept

Blade pitch control has been extremely important for the development of Horizontal-Axis Wind Turbines (HAWTs), allowing for greater efficiency over a wider range of operational regimes when compared to rigid-bladed designs. For Vertical-Axis Wind Turbines (VAWTs), blade pitching is inherently more difficult due to a dependence of attack angle on turbine armature location, shaft speed, and wind speed. As a result, there have been very few practical pitch control schemes put forward for VAWTs, which may be a major reason why this wind turbine type enjoys a much lower market share as compared to HAWTs. To alleviate this issue, the flexible, straight-bladed vertical-axis turbine is presented, which can passively adapt its geometry to local aerodynamic loadings and serves as a low-cost blade pitch control strategy increasing efficiency and startup capabilities. Using two-dimensional fluid-structure action simulations, this novel concept is compared to an identical rigid one and is proven to be superior in terms of power coefficient due to decreased torque minima. Moreover, due to the flexible nature of the blades, the morphing turbine achieves less severe oscillatory loadings. As a result, the morphing blade design is expected to not only increase efficiency but also system longevity without additional system costs usually associated with active pitch control schemes.

Numerical Simulation and Virtual Reality Visualization of Horizontal and Vertical Axis Wind Turbines

2011 ◽  
Author(s):  
Nan Yan ◽  
Tyamo Okosun ◽  
Sanjit K. Basak ◽  
Dong Fu ◽  
John Moreland ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Virtual Reality ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Small Scale ◽  
Mechanical Resistance ◽  
Wind Flow ◽  
Horizontal Axis Wind Turbine ◽  
Immersive Environment

Virtual Reality (VR) is a rising technology that creates a computer-generated immersive environment to provide users a realistic experience, through which people who are not analysis experts become able to see numerical simulation results in a context that they can easily understand. VR supports a safe and productive working environment in which users can perceive worlds, which otherwise could be too complex, too dangerous, or impossible or impractical to explore directly, or even not yet in existence. In recent years, VR has been employed to an increasing number of scientific research areas across different disciplines, such as numerical simulation of Computational Fluid Dynamics (CFD) discussed in present study. Wind flow around wind turbines is a complex problem to simulate and understand. Predicting the interaction between wind and turbine blades is complicated by issues such as rotating motion, mechanical resistance from the breaking system, as well as inter-blade and inter-turbine wake effects. The present research uses CFD numerical simulation to predict the motion and wind flow around two types of turbines: 1) a small scale Vertical Axis Wind Turbine (VAWT) and 2) a small scale Horizontal Axis Wind Turbine (HAWT). Results from these simulations have been used to generate virtual reality (VR) visualizations and brought into an immersive environment to attempt to better understand the phenomena involved.

scholarly journals Parametric Analysis Using CFD to Study the Impact of Geometric and Numerical Modeling on the Performance of a Small Scale Horizontal Axis Wind Turbine

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 505
Author(s):  
Muhammad Salman Siddiqui ◽  
Muhammad Hamza Khalid ◽  
Abdul Waheed Badar ◽  
Muhammed Saeed ◽  
Taimoor Asim
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Reference Frames ◽  
Horizontal Axis ◽  
Small Scale ◽  
High Fidelity ◽  
Horizontal Axis Wind Turbine ◽  
Rapid Variability ◽  
The Impact ◽  
Numerical Complexity

The reliance on Computational Fluid Dynamics (CFD) simulations has drastically increased over time to evaluate the aerodynamic performance of small-scale wind turbines. With the rapid variability in customer demand, industrial requirements, economic constraints, and time limitations associated with the design and development of small-scale wind turbines, the trade-off between computational resources and the simulation’s numerical accuracy may vary significantly. In the context of wind turbine design and analysis, high fidelity simulation under full geometric and numerical complexity is more accurate but pose significant demands from a computational standpoint. There is a need to understand and quantify performance deterioration of high fidelity simulations under reduced geometric or numerical approximation on a single small scale turbine model. In the present work, the flow past a small-scale Horizontal Axis Wind Turbine (HAWT) was simulated under various geometric and numerical configurations. The geometric complexity was varied based on stationary and rotating turbine conditions. In the stationary case, simple 2D airfoil, 2.5D blade, 3D blade sections are evaluated, while rotational effects are introduced for the configuration 3D blade, rotor only, and the full-scale wind turbine with and without the inclusion of a nacelle and tower. In terms of numerical complexity, the Single Reference Frame (SRF), Multiple Reference Frames (MRF), and the Sliding Meshing Interface (SMI) is analyzed over Tip Speed Ratios (TSR) of 3, 6, 10. The quantification of aerodynamic coefficients of the blade (Cl, Cd) and turbine (Cp, Ct) was conducted along with the discussion on wake patterns in comparison with experimental data.

Optimization of Power and Operation Characteristics of a New External Axis Wind Turbine

2016 ◽  
Author(s):  
Mst Sunzida Ferdoues ◽  
Sasan Ebrahimi ◽  
Krishna Vijayaraghavan
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Low Cost ◽  
Vertical Axis ◽  
Optimal Operation ◽  
Horizontal Axis Wind Turbine ◽  
Cfd Simulations ◽  
New Class ◽  
Operation Speed ◽  
Time Required

A new class of wind turbine termed the external axis wind turbine (EAWT) has been recently developed. The EAWT is a new class of wind turbines that combines the low cost of vertical axis wind turbines with the high power of horizontal axis wind-turbine. This paper is a first step study that assumes a constant wind speed and a simple on-off controller. The paper optimizes the number of blades in the EAWT and the time at which the controller must be turned on to simultaneously maximize the power while minimizing the time required to reach optimal operation. The multi-objective optimization on the EAWT is performed on a response surface that is generated using Computational Fluid Dynamics (CFD) simulations. The turbulence model and mesh-sizing for the CFD simulations are validated against previously published experimental results on a buff body. To the best of authors’ knowledge, this paper is the first study to investigate changing blade count, and determining optimal operation speed to simultaneously maximize power, while minimizing the time needed to reach peak operational point in wind-turbines.

Unsteady Flow Analysis Around an Elliptic-Bladed Savonius-Style Wind Turbine

2014 ◽  
Author(s):  
Abhisek Banerjee ◽  
Sukanta Roy ◽  
Prasenjit Mukherjee ◽  
Ujjwal K. Saha
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Low Cost ◽  
Turbine Blades ◽  
Flow Analysis ◽  
Experimental Studies ◽  
Flow Characteristics ◽  
Small Scale ◽  
Circular Design

Although considerable progress has already been achieved in the design of wind turbines, the available technical designs are not yet adequate to develop a reliable wind energy converter especially meant for small-scale applications. The Savonius-style wind turbine appears to be particularly promising for the small-scale applications because of its design simplicity, good starting ability, insensitivity to wind directions, relatively low operating speed, low cost and easy installation. However, its efficiency is reported to be inferior as compared to other wind turbines. Aiming for that, a number of investigations have been carried out to increase the performance of this turbine with various blade shapes. In the recent past, investigations with different blade geometries show that an elliptic-bladed turbine has the potential to harness wind energy more efficiently. In view of this, the present study attempts to assess the performance of an elliptic-bladed Savonius-style wind turbine using 2D unsteady simulations. The SST k-ω turbulence model is used to simulate the airflow over the turbine blades. The power and torque coefficients are calculated at rotating conditions, and the results obtained are validated with the wind tunnel experimental data. Both the computational and experimental studies indicate a better performance with the elliptical blades. Further, the present analysis also demonstrates improved flow characteristics of the elliptic-bladed turbine over the conventional semi-circular design.

Experimental and Numerical Investigations on Drag and Torque Characteristics of Three-Bladed Savonius Wind Turbine

2009 ◽  
Author(s):  
Mosfequr Rahman ◽  
Khandakar N. Morshed ◽  
Jeffery Lewis ◽  
Mark Fuller
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Vertical Axis ◽  
The United States ◽  
Small Scale ◽  
Horizontal Axis Wind Turbine ◽  
Drag Coefficients ◽  
Vertical Axis Wind Turbines ◽  
Torque Coefficient ◽  
Savonius Wind Turbine

With the growing demand of energy worldwide, conventional energy is becoming more and more scarce and expensive. The United States is already facing an energy crunch as the fuel price soars. Therefore, there is an obvious need for alternative sources of energy—perhaps more than ever. Wind is among the most popular and fastest-growing forms of electricity generation in the world, which is pollution free and available almost at any time of the day, especially in the coastal regions. The main attraction of the vertical-axis wind turbine is its manufacturing simplicity compared to that of the horizontal-axis wind turbine. Among all different vertical axis wind turbines, Savonius wind turbine is the simplest one. Operation of the Savonius wind turbine is based on the difference of the drag force on its semi-spherical blades, depending on whether the wind is striking the convex or the concave part of the blades. The advantage of this type of wind turbine is its good self-starting and wind directional independence characteristic. It, however, has a relatively lower efficiency in comparison with the lift type vertical-axis wind turbines. Due to its simple design and low construction cost, Savonius rotors are primarily used for water pumping and wind power on a small scale. The main objective of this ongoing research work is to improve the aerodynamic performance of vertical axis Savonius wind turbine. Wind tunnel investigation has been performed on aerodynamic characteristics, such as drag coefficients, and static torque coefficient of three-bladed Savonius rotor model. Also the computational fluid dynamics (CFD) simulation has been performed using FLUENT software to analyze the static rotor aerodynamics such as drag coefficients and torque coefficient, and these results are compared with the corresponding experimental results for verification.

Development and Field Test Performance of a Non-Conventional Unidirectional Co-Axial Two Series Rotors Micro Wind Turbine

2013 ◽  
Vol 768 ◽  
pp. 119-123
Author(s):  
Sandip A. Kale ◽  
S.N. Sapali
Keyword(s):  
Wind Turbine ◽  
Field Test ◽  
Wind Turbines ◽  
Power Output ◽  
Test Performance ◽  
Rural Population ◽  
Direct Drive ◽  
Wake Effect ◽  
Small Wind Turbines ◽  
Large Wind

The technology of harnessing wind energy through traditional three-bladed large wind turbines is in mature state. There are many disputes about the performance and availability of power output of the small wind turbines. The small wind turbines need improvement in technology for low speed starting behavior, enhancement in coefficient in performance, assured power output in low wind region. This work consists of development and field test performance of a non-conventional unidirectional co-axial two series rotors micro wind turbine to supply electricity for rural population. The unidirectional co-axial series rotor wind turbine consists of small rotors to replace a big rotor, mounted on a tilted long driveshaft at appropriate distances to face fresh wind, coupled to a direct drive generator. The developed turbine consists of two rotors, placed at suitable interval to avoid the wake effect. This work also includes field test performance and its analysis.

Assessment of a Modified Blade Element Momentum Methodology for Diffuser Augmented Wind Turbines

2017 ◽  
Author(s):  
Stavros N. Leloudas ◽  
Georgios N. Lygidakis ◽  
Ioannis K. Nikolos
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Power Output ◽  
Horizontal Axis Wind Turbine ◽  
Correction Model ◽  
Short Period ◽  
Turbine Design ◽  
The Impact ◽  
Bem Theory ◽  
Blade Element

The Blade Element Momentum (BEM) theory is nowadays the cornerstone of the horizontal axis wind turbine design, as its application allows for the accurate aerodynamic simulation and power output prediction of wind turbine rotors in a remarkably short period of time. Therefore, efforts have been made for the extension of the classic BEM theory to the performance analysis of Diffuser Augmented Wind Turbines (DAWTs) as well. In this study, the development and assessment of such an in-house BEM code are presented. The proposed computational model is based on the modification of the momentum part of the classical BEM theory; thus, it is capable to account for the diffuser’s effect on the calculation of the axial and tangential induction factors, through the utilization of the velocity speed-up distribution over the rotor plane of the unloaded diffuser. Furthermore, a detailed Glauert’s correction model, which employs Buhl’s modification, specially tailored for the DAWT case is included, to deal with the high values of the axial induction factor. The accuracy of the model is assessed against numerical and experimental results available in the literature, while the impact of the Prandtl’s tip loss correction model on the rotor’s predicted power output is also examined.

Development of a High Efficiency and Long Life 500W Class H-Darrieus Type VAWT (Vertical Axis Wind Turbine) System Using Skin-Spar-Foam Sandwich Composite Structure

2012 ◽  
Author(s):  
Changduk Kong ◽  
Haseung Lee
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Large Scale ◽  
Performance Test ◽  
High Efficiency ◽  
Vertical Axis ◽  
Small Scale ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Structural Test

Since the energy crisis and the environmental issue have been focused due to excessive fossil fuel consumption, the wind power has been considered as an important renewable energy source. Recently, several MW class large scale wind turbine systems have been developed in some countries. Even though the large scale wind turbine can effectively produce the electrical power, the small scale wind turbines have been continuously developed due some advantages, for instance, it can be easily built by low cost without any limitation of location, i.e. even in city. In case of small scale wind turbines, the vertical axis wind turbine (VAWT) is used in city having frequent wind direction change, even though it has a bit lower efficient than the horizontal axis wind turbine. Furthermore, most small scale wind turbine systems have been designed at the rated wind speed of around 12m/s. This work is to design a high efficiency 500W class composite VAWT blade which is applicable to relatively low speed region. In the aerodynamic design of blade, the parametric studies are carried out to decide an optimal aerodynamic configuration. The aerodynamic efficiency and performance of the designed VAWT is confirmed by the CFD analysis. The structural design is performed by the load case study, the initial sizing using the netting rule and the rule of mixture, the structural analysis using FEM, the fatigue life estimation and the structural test. The prototype blade is manufactured by the hand lay-up and the matched die molding. The experimental structural test results are compared with the FEM analysis results. Finally, to evaluate the prototype VAWT including designed blades, the performance test is performed using a truck to simulate the various range wind speeds and some measuring equipments. According to the performance evaluation result, the estimated performance is well agreed with the experimental test result in all operating ranges.

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