Circulation Control Applied to Wind Turbines

2009 ◽  
Author(s):  
David McGrain ◽  
Gerald M. Angle ◽  
Jay P. Wilhelm ◽  
Emily D. Pertl ◽  
James E. Smith
Keyword(s):  
Wind Energy ◽  
Wind Turbines ◽  
Power Output ◽  
Alternative Energy ◽  
Vertical Axis ◽  
Limiting Factor ◽  
Circulation Control ◽  
Bird Populations ◽  
Horizontal Axis Wind Turbines ◽  
The Impact

The recent rise in fuel costs and global warming concerns have re-invigorated the search for alternative energy sources. Harnessing energy from the wind is a logical alternative; however the cost and efficiency of current wind turbines is a limiting factor. The use of an augmented Vertical Axis Wind Turbines (VAWTs) may become the superior choice to the more common Horizontal Axis Wind Turbines (HAWTs) that are usually associated with the harvesting of wind energy. HAWTs operate on the same principles as large airplane propellers, while VAWTs operate on lift and/or drag principles like an airplane wing or a sail on a boat. VAWTs are currently being investigated for use with circulation control to increase their potential power output. In this paper, two topics will be presented, a comparison between VAWTs and HAWTs for rotor diameter versus key turbine aspects and the impact of VAWTs on environmental concerns, such as bat and bird populations. The Center for Industrial Research Applications (CIRA) at West Virginia University (WVU) is currently developing a concept utilizing circulation control to increase the lift to drag ratio, maximizing the beneficial forces on the VAWT blade, allowing for improved wind energy production. For the comparison between VAWTs and HAWTs, there are currently 14 companies with a total of 34 wind turbines variations representing VAWTs and 11 companies with a total of 40 wind turbines representing HAWTs. Trend studies of VAWT and HAWT diameters to cut-in-speed, rated velocity, max velocity, power output (<100 kW), and power output (≥100 kW) were created to show the potential of VAWTs. A growing concern with wind energy is the impact on bat and bird populations. It is currently believed that VAWTs reduce the impact of wind energy by altering the interaction with the wind. If these benefits can be proven, then not only are VAWTs potentially more economical, but even more eco-friendly.

Development and Application of a Simulation Tool for Vertical and Horizontal Axis Wind Turbines

2013 ◽  
Author(s):  
David Marten ◽  
Juliane Wendler ◽  
Georgios Pechlivanoglou ◽  
Christian Navid Nayeri ◽  
Christian Oliver Paschereit
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Horizontal Axis ◽  
Vertical Axis Wind Turbine ◽  
First Case ◽  
Horizontal Axis Wind Turbines ◽  
Lift And Drag ◽  
The Impact

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.

Numerical Study of Airfoil Shape and Blade Pitching on Vertical Axis Wind Turbine Through CFD Simulations

2020 ◽  
Author(s):  
Ussama Ali ◽  
Mhd Modrek ◽  
Md Islam ◽  
Isam Janajreh
Keyword(s):  
Wind Energy ◽  
Wind Turbines ◽  
Numerical Study ◽  
Electrical Power ◽  
Vertical Axis ◽  
Low Noise ◽  
Vertical Axis Wind Turbine ◽  
Noise Emission ◽  
Flow Models ◽  
Horizontal Axis Wind Turbines

Abstract Wind energy has proved to be a promising sustainable energy source; the energy of wind has been harvested not only for decades but for centuries. It was in the late 19th century that wind energy was used to directly obtain electrical power. Horizontal axis wind turbines (HAWTs) are widely used in commercial applications but recently a lot of research is being done on vertical axis wind turbines (VAWTs) to improve their operation and efficiency. Absence of yaw mechanism, low noise emission, and low manufacturing, installation and maintenance costs are some of the prominent advantages of VAWT over HAWT. The objective of this study is to evaluate the performance of different blade airfoils and the influence of blade pitching in the operation of VAWT. Blade pitching is widely used in HAWTs and has proven to be very advantageous in terms of output power, but the effect of blade pitching on VAWT has not been widely studied and much less practically implied due to complex functional mechanism. VAWTs with fixed pitch experience continuously varying angle of attack which reduces the power generation. Airfoils tested in this study, for their performance on a VAWT rotor, are Joukowski airfoil (J-15), NACA0012 and NACA4312, furthermore, passive blade pitching was applied to analyze the effect of inoffset and out-offset blade pitching on the performance of the turbine. High fidelity Navier-Stokes computational flow models were applied for the analysis. A 2D unsteady CFD model was constructed to perform the simulations. Power and torque coefficients were evaluated over a varying range of tip speed ratios and a strong correlation of these coefficients was seen with different input parameters, such as airfoil shape, turbine solidity and tip speed ratios. Out-offset blade pitch angles showed better results than in-offset blade pitch angles.

scholarly journals Aerodynamic Simulations for Floating Darrieus-Type Wind Turbines with Three-Stage Rotors

Inventions ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 18
Author(s):  
Mohamed Amine Dabachi ◽  
Abdellatif Rahmouni ◽  
Eugen Rusu ◽  
Otmane Bouksour
Keyword(s):  
Wind Energy ◽  
Wind Turbines ◽  
Energy Demand ◽  
Fossil Fuels ◽  
Cost Effective ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Critical Parameters ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbines

Growing energy demand is causing a significant decrease in the world’s hydrocarbon stock in addition to the pollution of our ecosystem. Based on this observation, the search for alternative sorts of energy to fossil fuels is being increasingly explored and exploited. Wind energy is experiencing a very important development, and it offers a very profitable opportunity for exploitation since the wind is always available and inexhaustible. Several technical solutions exist to exploit wind energy, such as floating vertical axis wind turbines (F-VAWTs), which provide an attractive and cost-effective solution for exploiting higher resources of offshore wind in deep water areas. Recently, the use of the Darrieus vertical axis wind turbine (VAWT) offshore has attracted increased interest because it offers significant advantages over horizontal axis wind turbines (HAWTs). In this context, this article presents a new concept of floating Darrieus-type straight-bladed turbine with three-stage rotors. A double-multiple stream tube (DMST) model is used for aerodynamic simulations to examine several critical parameters, including, solidity turbine, number of blades, rotor radius, aspect ratio, wind velocity, and rotor height. This study also allows to identify a low solidity turbine (σ = 0.3), offering the best aerodynamic performance, while a two-bladed design is recommended. Moreover, the results also indicate the interest of a variable radius rotor, as well as the variation of the height as a function of the wind speed on the aerodynamic efficiency.

A Numerical Study on the Performance Improvement for a Vertical-Axis Wind Turbine at Low Tip-Speed-Ratios

2017 ◽  
Author(s):  
Zhenyu Wang ◽  
Mei Zhuang
Keyword(s):  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbines ◽  
Flow Separation ◽  
Power Output ◽  
Numerical Study ◽  
Leading Edge ◽  
Vertical Axis ◽  
Dynamic Stall ◽  
Energy Extraction

Vertical-axis wind turbines (VAWTs) are a promising solution for the use of renewable energy in residential areas. Compared to traditional horizontal-axis wind turbines (HAWTs), VAWTs are usually smaller, quieter, and insensitive to the wind direction and can be installed in a wide range of urban, suburban and rural places such as top of buildings, backyard, etc. In addition, VAWTs require a lower wind speed to self-start which increases the capability of wind energy extraction in the areas with low wind speed. However, VAWTs are less efficient and the power output of VAWTs is substantially affected by the phenomenon of dynamic stall induced by the variations of angle of attack of rotating blades, especially at low tip speed ratios (λTSR<4). When the dynamic stall vortices, formed near the leading-edge, are transported downstream, it creates large and sudden fluctuations in torques. At low values of the tip speed ratio and relatively low Reynolds number (Re<105), dynamic stall occurs periodically throughout the rotation of the blades. This results a sharp drop in lift coefficient and therefore rotor torque and power output are substantially reduced. The purpose of the present study is to investigate the prospects for improving the flow performances of small VAWTs using serrated leading-edge configurations on straight blades in a conventional H-type VAWT design to control dynamic flow separation. A numerical study is carried out to obtain the detailed flow fields for analysis and visualization. The results show that the turbine blade with the serration profiles of h = 0.025c (amplitude) and λs = 0.33c (wavelength) not only increased the power generation at low TSRs, but also enhanced the capability of wind energy extraction at the optimum TSR in comparison to the baseline model. The dynamic stall was suppressed significantly in the range of the azimuth angle from 80° to 160°. The flow separation induced by large angles of attack was essentially alleviated in the modified turbine model due to the serrated configuration implemented on the blade leading-edge.

scholarly journals VERTICAL AXIS WIND TURBINE DESIGN FOR MOVEMENT PERMANENT MAGNETIC GENERATORS OF AXIAL TYPE

Tibuana ◽  
2019 ◽  
Vol 2 (02) ◽  
pp. 58-67
Author(s):  
Budi prijo Sembodo
Keyword(s):  
Power Plant ◽  
Wind Energy ◽  
Wind Turbines ◽  
Alternative Energy ◽  
Coastal Region ◽  
Electrical Energy ◽  
Vertical Axis ◽  
Material Strength ◽  
Vertical Axis Wind Turbine ◽  
Energy Potential

One of  the alternative energy source that can be developed is the Wind Power Plant. The need for electrical energy that continues to increase, it takes not a little time to build a power plant. System planners must also be able to see the possibilities of the development of the power system in the years to come. Indonesia is a country that has abundant energy resources, one of which is a source of wind energy. Indonesia which is an archipelagic country and one of the countries located on the equator is a factor, that Indonesia has abundant wind energy potential. In this study the output that produced is a renewable energy product, which is a power plant product in the coastal area. In the previous study a low-speed permanent magnet generator has been produced which can be driven by wind turbines which will be continued through the design of vertical type wind turbines. The results of this study can then be developed, especially for electricity generation products in the coastal region. In the process of planning and manufacturing vertical type wind turbines, to produce enough power to meet household electricity needs should be based on several factors that support the effectiveness of the power produced by the turbine, namely: Turbine Dimensions (Length and Blade Width), Material Strength , Shaft, Bearing and Generator Shaft

scholarly journals Optimal Design of Novel Blade Profile for Savonius Wind Turbines

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3484
Author(s):  
Tai-Lin Chang ◽  
Shun-Feng Tsai ◽  
Chun-Lung Chen
Keyword(s):  
Wind Energy ◽  
Drag Force ◽  
Wind Turbines ◽  
Rural Areas ◽  
Large Scale ◽  
Design Method ◽  
Angular Position ◽  
Vertical Axis ◽  
Blade Profile ◽  
Main Concept

Since the affirming of global warming, most wind energy projects have focused on the large-scale Horizontal Axis Wind Turbines (HAWTs). In recent years, the fast-growing wind energy sector and the demand for smarter grids have led to the use of Vertical Axis Wind Turbines (VAWTs) for decentralized energy generation systems, both in urban and remote rural areas. The goals of this study are to improve the Savonius-type VAWT’s efficiency and oscillation. The main concept is to redesign a Novel Blade profile using the Taguchi Robust Design Method and the ANSYS-Fluent simulation package. The convex contour of the blade faces against the wind, creating sufficient lift force and minimizing drag force; the concave contour faces up to the wind, improving or maintaining the drag force. The result is that the Novel Blade improves blade performance by 65% over the Savonius type at the best angular position. In addition, it decreases the oscillation and noise accordingly. This study achieved its two goals.

Optimal Placement of Horizontal- and Vertical-Axis Wind Turbines in a Wind Farm for Maximum Power Generation Using a Genetic Algorithm

2011 ◽  
Author(s):  
Xiaomin Chen ◽  
Ramesh Agarwal
Keyword(s):  
Genetic Algorithm ◽  
Wind Turbines ◽  
Wind Farm ◽  
Optimization Problem ◽  
Vertical Axis ◽  
Optimal Placement ◽  
Vertical Axis Wind Turbines ◽  
Wake Effects ◽  
Horizontal Axis Wind Turbines ◽  
Wake Model

In this paper, we consider the Wind Farm layout optimization problem using a genetic algorithm. Both the Horizontal–Axis Wind Turbines (HAWT) and Vertical-Axis Wind Turbines (VAWT) are considered. The goal of the optimization problem is to optimally place the turbines within the wind farm such that the wake effects are minimized and the power production is maximized. The reasonably accurate modeling of the turbine wake is critical in determination of the optimal layout of the turbines and the power generated. For HAWT, two wake models are considered; both are found to give similar answers. For VAWT, a very simple wake model is employed.

Vertical axis wind turbine operation in icing conditions: A review study

2021 ◽  
pp. 0309524X2110618
Author(s):  
Syed Abdur Rahman Tahir ◽  
Muhammad Shakeel Virk
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Electricity Production ◽  
Vertical Axis Wind Turbine ◽  
Vertical Axis Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
Promising Solution ◽  
Review Study ◽  
Accretion Physics

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.

Techno-Economic Assessment of Utilizing Wind Energy for Hydrogen Production Through Electrolysis

2017 ◽  
Author(s):  
Reza Ziazi ◽  
Kasra Mohammadi ◽  
Navid Goudarzi
Keyword(s):  
Hydrogen Production ◽  
Wind Energy ◽  
Wind Turbines ◽  
Alternative Energy ◽  
Large Scale ◽  
Fossil Fuels ◽  
Combustion Engine ◽  
Economic Assessment ◽  
Large Cities ◽  
North East

Hydrogen as a clean alternative energy carrier for the future is required to be produced through environmentally friendly approaches. Use of renewables such as wind energy for hydrogen production is an appealing way to securely sustain the worldwide trade energy systems. In this approach, wind turbines provide the electricity required for the electrolysis process to split the water into hydrogen and oxygen. The generated hydrogen can then be stored and utilized later for electricity generation via either a fuel cell or an internal combustion engine that turn a generator. In this study, techno-economic evaluation of hydrogen production by electrolysis using wind power investigated in a windy location, named Binaloud, located in north-east of Iran. Development of different large scale wind turbines with different rated capacity is evaluated in all selected locations. Moreover, different capacities of electrolytic for large scale hydrogen production is evaluated. Hydrogen production through wind energy can reduce the usage of unsustainable, financially unstable, and polluting fossil fuels that are becoming a major issue in large cities of Iran.

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