Optimization of Power and Operation Characteristics of a New External 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.

Comparison of horizontal axis wind turbine (HAWT) and vertical axis wind turbine (VAWT)

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.13.21333 ◽

2018 ◽

Vol 7 (4.13) ◽

pp. 74 ◽

Cited By ~ 9

Author(s):

Muhd Khudri Johari ◽

Muhammad Azim A Jalil ◽

Mohammad Faizal Mohd Shariff

Keyword(s):

Wind Turbine ◽

Wind Turbines ◽

Vertical Axis ◽

Green Technology ◽

Horizontal Axis ◽

Current Output ◽

Voltage Output ◽

And Performance

As the demand for green technology is rising rapidly worldwide, it is important that Malaysian researchers take advantage of Malaysia’s windy climates and areas to initiate more power generation projects using wind. The main objectives of this study are to build a functional wind turbine and to compare the performance of two types of design for wind turbine under different speeds and behaviours of the wind. A three-blade horizontal axis wind turbine (HAWT) and a Darrieus-type vertical axis wind turbine (VAWT) have been designed with CATIA software and constructed using a 3D-printing method. Both wind turbines have undergone series of tests before the voltage and current output from the wind turbines are collected. The result of the test is used to compare the performance of both wind turbines that will imply which design has the best efficiency and performance for Malaysia’s tropical climate. While HAWT can generate higher voltage (up to 8.99 V at one point), it decreases back to 0 V when the wind angle changes. VAWT, however, can generate lower voltage (1.4 V) but changes in the wind angle does not affect its voltage output at all. The analysis has proven that VAWT is significantly more efficient to be built and utilized for Malaysia’s tropical and windy climates. This is also an initiative project to gauge the possibility of building wind turbines, which could be built on the extensive and windy areas surrounding Malaysian airports.

The Straight-Bladed Morphing Vertical Axis Wind Turbine

ASME 2016 Power Conference ◽

10.1115/power2016-59192 ◽

2016 ◽

Author(s):

David MacPhee ◽

Asfaw Beyene

Keyword(s):

Wind Turbine ◽

Wind Turbines ◽

Low Cost ◽

Vertical Axis ◽

Power Coefficient ◽

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.

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

A comparison between the dynamics of horizontal and vertical axis offshore floating wind turbines

10.1098/rsta.2014.0076 ◽

2015 ◽

Vol 373 (2035) ◽

pp. 20140076 ◽

Cited By ~ 21

Author(s):

M. Borg ◽

M. Collu

Keyword(s):

Wind Turbine ◽

Wind Turbines ◽

Vertical Axis ◽

Static Stability ◽

Dynamic Responses ◽

Offshore Wind ◽

Frequency Range ◽

Aerodynamic Forces ◽

Support Structure

The need to further exploit offshore wind resources in deeper waters has led to a re-emerging interest in vertical axis wind turbines (VAWTs) for floating foundation applications. However, there has been little effort to systematically compare VAWTs to the more conventional horizontal axis wind turbine (HAWT). This article initiates this comparison based on prime principles, focusing on the turbine aerodynamic forces and their impact on the floating wind turbine static and dynamic responses. VAWTs generate substantially different aerodynamic forces on the support structure, in particular, a potentially lower inclining moment and a substantially higher torque than HAWTs. Considering the static stability requirements, the advantages of a lower inclining moment, a lower wind turbine mass and a lower centre of gravity are illustrated, all of which are exploitable to have a less costly support structure. Floating VAWTs experience increased motion in the frequency range surrounding the turbine [number of blades]×[rotational speed] frequency. For very large VAWTs with slower rotational speeds, this frequency range may significantly overlap with the range of wave excitation forces. Quantitative considerations are undertaken comparing the reference NREL 5 MW HAWT with the NOVA 5 MW VAWT.

Volume 2: 31st Computers and Information in Engineering Conference, Parts A and B ◽

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

10.1115/detc2011-47969 ◽

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 ◽

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.

Modelo Teórico de los Sistemas de Aerogeneración Eléctrica para las Turbinas Eólicas de Eje Vertical

Revista ECIPeru ◽

10.33017/reveciperu2009.0027/ ◽

2019 ◽

pp. 68-76

Keyword(s):

Theoretical Model ◽

Wind Turbine ◽

Wind Turbines ◽

Magnetic Induction ◽

Magnetic Levitation ◽

Vertical Axis ◽

Advantages And Disadvantages ◽

Levitation System

Modelo Teórico de los Sistemas de Aerogeneración Eléctrica para las Turbinas Eólicas de Eje Vertical Theoretical Model of Electric Aerogeneration Systems for Vertical Axis Wind Turbines Anthony Pinedo, Guillermo Ramírez, Lincoln Chiguala, Juan Estrada, David Asmat, Renny Nazario, Daniel Delfín, Lourdes Noriega, Silvia Aguilar, Randy Rosas, Luisa Juárez DOI: https://doi.org/10.33017/RevECIPeru2009.0027/ RESUMEN Existen dos tipos de sistemas de aerogeneración eléctrica por turbinas eólicas, los llamados de eje horizontal (HAWT) y los de eje vertical (VAWT). Ambos proponen ventajas y desventajas, dependiendo de muchos factores. Pero en general, no fue hasta hace unos años que el segundo tipo había sido ignorado, debido a la poca potencia que producía en comparación con los HAWT. Pero con la adaptación de un sistema de levitación, y un nuevo sistema de inducción magnética, las VAWT, lograron incrementar notablemente la energía obtenida, llegando incluso a superar a los HAWT. A pesar que los modelos VAWT han sido harto estudiados en cuanto al esquema experimental y de diseño, no se formuló ninguna explicación sólida, partiendo de principios básicos, sobre el funcionamiento de los VAWT. En este trabajo, se propone un modelo teórico del funcionamiento de los mismos. Para ello, se realizan tres estudios: la interacción del viento con las aspas del aerogenerador, el sistema de levitación magnética y la producción de energía eléctrica por inducción magnética. Estos tres fenómenos, permiten definir y predecir el funcionamiento de tal sistema de aerogeneración. Además, permite «visualizar» la influencia de los diferentes parámetros sobre la eficiencia del sistema, y así pues, poder manejar, los parámetros que controlamos experimentalmente, para obtener una eficiencia óptima. Palabras clave: aerogeneración eléctrica, turbinas de aire, eje vertical, levitación magnética. ABSTRACT There are two types of systems of electric aerogeneration by using wind turbines, one is called horizontal axis wind turbine (HAWT) and the other one is called vertical axis wind turbine (VAWT). Both of them have advantages and disadvantages depending on many factors. Since the second one had produced lees power than the first one, they were ignored. However, the adaptation of a levitation system and a new system of magnetic induction made VAWT increase the power produced and exceed the HAWT. Although VAWT models were studied enough in the design and experimental scheme, there is no solid explanation, based on basic principles, on the operation of the VAWT. In this paper is proposed a theoretical model of VAWT operation. Therefore, three studies are done: the interaction between wind and blades of the turbine, the magnetic levitation system and the energy production by magnetic induction. Those studies make us able to know and predict the operation of those systems. Since, we shall know how many factors are affecting the efficiency of the system; we shall be able to control those parameters in order to get the best efficiency. Keywords: electric aerogeneration, vertical axis wind turbine, magnetic levitation.

Influence of wind energy utilization potential in urban suburbs: a case study of Hohhot

Scientific Reports ◽

10.1038/s41598-021-90499-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Wang Wenxin ◽

Chen Kexin ◽

Bai Yang ◽

Xu Yun ◽

Wang Jianwen

Keyword(s):

Wind Speed ◽

Wind Energy ◽

Wind Turbine ◽

Wind Turbines ◽

Vertical Axis ◽

Statistical Properties ◽

Energy Utilization ◽

Energy Output ◽

Distribution Model ◽

Horizontal Axis Wind Turbine

AbstractGiven the increasing trend of using wind energy in cities, the utilization of distributed wind energy in cities has been widely concerned by researchers. The related research on the micro-site selection of wind turbines, a sub-project of the Task27 project of the International energy agency, was continued in this paper. The wind speed data of an observation station near Hohhot, Inner Mongolia, with a range of 10–19 m were collected. The evaluation included wind direction, Weibull parameter characteristics, and turbulence intensity. The potential energy output in 10 different heights was estimated using commercial horizontal and vertical axis wind turbines of the same power. Results showed that the following: the three-parameter Weibull distribution model can well describe the statistical properties of the wind speed in this site. The wind speed distribution model constructed from extrapolation parameters reflects the wind speed statistical properties out of detection positions to a certain extent. The wind energy density of the vertical axis wind turbine is slightly lower than that of the horizontal axis wind turbine. Furthermore, more power can be generated from March to May.

Fabrication and Performance Evaluation of Savonious Vertical Axis Wind Turbine for Uncertain Speed Regions

International Journal of Thermal and Environmental Engineering ◽

10.5383/ijtee.13.02.005 ◽

2017 ◽

Vol 13 (2) ◽

Keyword(s):

Performance Evaluation ◽

Wind Turbine ◽

Wind Turbines ◽

Urban Areas ◽

Vertical Axis ◽

Design Parameters ◽

Vertical Axis Wind Turbines ◽

And Performance

The consumption of electricity in urban as well as rural is increasing every day and became an essential commodity for household and industrial purposes. Unfortunately the availability of electrical energy in India is not sufficient to the required demand and it is essential to discover and generate energy from non-conventional sources with cheap cost. On the same time it is necessary to reduce the consumption of conventional sources and to save fuel. Among all the renewable resources, wind is one of the best resources available all the time at free of cost. Especially vertical axis wind turbines (VAWT) are self-starting, omni directional. They require no yaw mechanism to continuously orient towards the wind direction and provide a more reliable energy conversion technology, as compared to horizontal axis wind turbine. Particularly savonius vertical axis wind turbines (SVAWT) are suitable and practically possible at low or uncertain wind speed regimes. They can be fitted on rooftops and also suitable for the urban areas where electricity is not available properly. This project deals with the fabrication and performance evaluation of savonius vertical axis wind turbine using two blade rotor. The amount of power developed by the wind turbine is calculated under theoretical and practical conditions and aerodynamics coefficients are also estimated. And various design parameters of savonious rotor are identified and determined.

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

Renewable Energy and Power Quality Journal ◽

10.24084/repqj19.253 ◽

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 ◽

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.

Volume 6: Emerging Technologies: Alternative Energy Systems; Energy Systems: Analysis, Thermodynamics and Sustainability ◽

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

10.1115/imece2009-10838 ◽

2009 ◽

Cited By ~ 1

Author(s):

Mosfequr Rahman ◽

Khandakar N. Morshed ◽

Jeffery Lewis ◽

Mark Fuller

Keyword(s):

Wind Turbine ◽

Wind Turbines ◽

Vertical Axis ◽

The United States ◽

Small Scale ◽

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.

A New Structure for Low Speed Wind Turbine in Built-Up Areas

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.860-863.314 ◽

2013 ◽

Vol 860-863 ◽

pp. 314-318

Author(s):

Feng Ji ◽

Xiao Jian Feng ◽

Dong Liang Wang

Keyword(s):

Growth Rate ◽

Wind Turbine ◽

Wind Velocity ◽

Wind Turbines ◽

Residential Building ◽

Vertical Axis ◽

Low Speed

Traditional wind turbines are difficulty to work well in built-up areas due to wind conditions of low speed, turbulence and frequent changing direction. A long-term wind observation work has been done to understand the characteristics of urban wind by installing a small weather station on the balcony at top floor of a residential building. Based on the observation results, a new structure for low speed wind turbine in built-up areas was designed. This structure can be used for either horizontal axis wind turbine or vertical axis wind turbine. Some mesh models were established to simulate the effect through CFD software. In this structure, growth rate of wind velocity is about 1.25 times; wind turbulence converts to laminar; and yawing angel of turbine motor shafts neednt change any more. Prototype testing draws better conclusions: growth rate of wind velocity is more than 1.4 times. Therefore, traditional wind turbines can work well in built-up areas through this new structure.