Yaw Control of Small Wind Turbines With a New Passive Tail Device: Part 1 — Steady-State Case

Solar Energy ◽  
2003 ◽  
Author(s):  
Eduardo Rinco´n Meji´a ◽  
Jesu´s Tovar Salazar ◽  
Jo´zef Wo´jcik Filipek

This paper describes the behavior of a new tail device to yaw smoothly small wind turbine rotors out of the wind during strong wind or gusts. The passive tail device consists of a rigid short tail, an aerodynamic rotating vane, a tail bumper, and a spring. This passive tail device reduces gyroscopic loads, is easy to adjust, can be manufactured in smaller sizes, and is much stronger than conventional vanes used in small wind machines. Besides, the energy collected with it is greater. Field test results indicate that its behavior agrees very well with simulations, and that the regulator can be advantageously utilized, as compared with conventional vanes and other mechanical or electromechanical means, in horizontal-axis wind turbines with diameters of 12 m or smaller. Here the steady-state case (quasi-steady wind velocity is assumed) is analyzed, showing the technical viability of the regulator proposed.

2013 ◽  
Vol 768 ◽  
pp. 119-123
Author(s):  
Sandip A. Kale ◽  
S.N. Sapali

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.


Author(s):  
Fabio De Bellis ◽  
Luciano A. Catalano ◽  
Andrea Dadone

The numerical simulation of horizontal axis wind turbines (HAWT) has been analysed using computational fluid dynamics (CFD) with the aim of obtaining reliable but at the same time affordable wind turbine simulations, while significantly reducing required overall resources (time, computational power, user skills), for example in an optimization perspective. Starting from mesh generation, time required to extract preliminary aerodynamic predictions of a wind turbine blade has been shortened by means of some simplifications, i.e.: fully unstructured mesh topology, reduced grid size, incompressible flow assumption, use of wall functions, commercial available CFD package employment. Ansys Fluent software package has been employed to solve Reynolds Averaged Navier Stokes (RANS) equations, and results obtained have been compared against NREL Phase VI campaign data. The whole CFD process (pre-processing, processing, postprocessing) has been analysed and the chosen final settings are the result of a trade-off between numerical accuracy and required resources. Besides the introduced simplifications, numerical predictions of shaft torque, forces and flow distribution are in good agreement with experimental data and as accurate as those calcuted by other more sophisticated works.


2021 ◽  
pp. 0309524X2110618
Author(s):  
Syed Abdur Rahman Tahir ◽  
Muhammad Shakeel Virk

Vertical Axis Wind Turbine (VAWT) can be a promising solution for electricity production in remote ice prone territories of high north, where good wind resources are available, but icing is a challenge that can affect its optimum operation. A lot of research has been made to study the icing effects on the conventional horizontal axis wind turbines, but the literature about vertical axis wind turbines operating in icing conditions is still scarce, despite the importance of this topic. This paper presents a review study about existing knowledge of VAWT operation in icing condition. Focus has been made in better understanding of ice accretion physics along VAWT blades and methods to detect and mitigate icing effects.


2014 ◽  
Vol 524 ◽  
pp. 012002 ◽  
Author(s):  
P A Fleming ◽  
A K Scholbrock ◽  
A Jehu ◽  
S Davoust ◽  
E Osler ◽  
...  

Author(s):  
David Marten ◽  
Juliane Wendler ◽  
Georgios Pechlivanoglou ◽  
Christian Navid Nayeri ◽  
Christian Oliver Paschereit

A double-multiple-streamtube vertical axis wind turbine simulation and design module has been integrated within the open-source wind turbine simulator QBlade. QBlade also contains the XFOIL airfoil analysis functionalities, which makes the software a single tool that comprises all functionality needed for the design and simulation of vertical or horizontal axis wind turbines. The functionality includes two dimensional airfoil design and analysis, lift and drag polar extrapolation, rotor blade design and wind turbine performance simulation. The QBlade software also inherits a generator module, pitch and rotational speed controllers, geometry export functionality and the simulation of rotor characteristics maps. Besides that, QBlade serves as a tool to compare different blade designs and their performance and to thoroughly investigate the distribution of all relevant variables along the rotor in an included post processor. The benefits of this code will be illustrated with two different case studies. The first case deals with the effect of stall delaying vortex generators on a vertical axis wind turbine rotor. The second case outlines the impact of helical blades and blade number on the time varying loads of a vertical axis wind turbine.


2014 ◽  
Vol 540 ◽  
pp. 96-105 ◽  
Author(s):  
Hong Mei Sun ◽  
Li Wei Hu ◽  
Jia Wen

Wind turbines typically run in harsh environments region, but the general requirements in the case of work unattended. Therefore, the brake system is a key component to protect the safe operation of wind turbines. When the wind turbine over speed occurs, overload or other abnormal conditions, the brake system needs to start immediately, so that the whole unit into the shutdown state to ensure crew safety. This article describes the role of wind turbine brake system, composition, operation principle, comparing the advantages and disadvantages of the most commonly used active and passive spindle brake doubly-fed wind turbine. Completion of a wind turbine import passive brake design, manufacturing localization, combined with wind turbine machine operating parameters, developed analytical test program brakes and the test results, and for the test questions are designed to improve.


Author(s):  
Sayem Zafar ◽  
Mohamed Gadalla

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.


2015 ◽  
Vol 764-765 ◽  
pp. 457-461 ◽  
Author(s):  
Shyh Kuang Ueng ◽  
Yao Hong Chan

This paper presents a Radar Cross Section (RCS) reduction method for wind turbines. In the proposed method, a reshaping procedure is utilized to generate waves or bumps on the surface of the wind-turbine tower. As the tower is illuminated by electromagnetic waves, the reflected rays are perturbed by the convex structures and the RCS of the wind turbine is decreased. Test results conclude that our modeling method reduces the average RCS values. The scatterings in the directions of the convex structures are significantly declined.


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