The Darrieus wind turbine is a type of vertical axis wind turbine (VAWT) used to generate electricity from wind energy. The turbine consists of a number of curved aerofoil blades mounted on a rotating shaft or framework. The curvature of the blades allows the blade to be stressed only in tension at high rotating speeds. There are several closely related wind turbines that use straight blades. This design of the turbine was patented by Georges Jean Marie Darrieus, a French aeronautical engineer; filing for the patent was October 1, 1926. There are major difficulties in protecting the Darrieus turbine from extreme wind conditions and in making it self-starting.
X-Plane is a flight simulation engine series developed and published by Laminar Research in 1995. Commercial desktop versions are sold for macOS, Windows, and Linux. In addition, Laminar Research also distributes FAA-certified versions for professional use. A mobile version has been available for Android, iOS, and webOS since 2009 as well.
The National Renewable Energy Laboratory (NREL) in the US specializes in the research and development of renewable energy, energy efficiency, energy systems integration, and sustainable transportation. NREL is a federally funded research and development center sponsored by the Department of Energy and operated by the Alliance for Sustainable Energy, a joint venture between MRIGlobal and Battelle. Located in Golden, Colorado, NREL is home to the National Center for Photovoltaics, the National Bioenergy Center, and the National Wind Technology Center.
In aeronautics, an aircraft propeller, also called an airscrew, converts rotary motion from an engine or other power source into a swirling slipstream which pushes the propeller forwards or backwards. It comprises a rotating power-driven hub, to which are attached several radial airfoil-section blades such that the whole assembly rotates about a longitudinal axis. The blade pitch may be fixed, manually variable to a few set positions, or of the automatically variable "constant-speed" type.
Wind turbine design is the process of defining the form and configuration of a wind turbine to extract energy from the wind. An installation consists of the systems needed to capture the wind's energy, point the turbine into the wind, convert mechanical rotation into electrical power, and other systems to start, stop, and control the turbine.
Unconventional wind turbines are those that differ significantly from the most common types in use.
CFD-FASTRAN is a commercial Computational Fluid Dynamics (CFD) software package developed by ESI Group for aerodynamic and aerothermodynamic applications. It employs multiple moving body capability for simulating problems such as missile launch, maneuvering and staging, and aircraft flight dynamics and store separation.
SAMCEF is a finite element analysis (FEA) software package dedicated to mechanical virtual prototyping. SAMCEF development started in 1965 at the Aerospace Laboratory of University of Liège. It was developed and sold by SAMTECH, a Belgian company, founded in 1986 and located in Liège, Belgium. SAMTECH s.a. was acquired by LMS in 2011.
Specialized wind energy software applications aid in the development and operation of wind farms.
A wind turbine is a device that converts the kinetic energy of wind into electrical energy. As of 2020, hundreds of thousands of large turbines, in installations known as wind farms, were generating over 650 gigawatts of power, with 60 GW added each year. Wind turbines are an increasingly important source of intermittent renewable energy, and are used in many countries to lower energy costs and reduce reliance on fossil fuels. One study claimed that, as of 2009, wind had the "lowest relative greenhouse gas emissions, the least water consumption demands and the most favorable social impacts" compared to photovoltaic, hydro, geothermal, coal and gas energy sources.
The primary application of wind turbines is to generate energy using the wind. Hence, the aerodynamics is a very important aspect of wind turbines. Like most machines, wind turbines come in many different types, all of them based on different energy extraction concepts.
Compact Wind Acceleration Turbines (CWATs) are a class of wind turbine that uses structures to accelerate wind before it enters the wind-generating element. The concept of these structures has been around for decades but has not gained wide acceptance in the marketplace. In 2008, two companies targeting the mid-wind marketplace have received funding from venture capital. The first company to receive funding is Optiwind, which received its series A funding in April 2008, and the second company is Ogin, Inc., which also received its series A funding in April 2008. Optiwind is funded through Charles River Ventures and FloDesign is funded through Kleiner Perkins. Other CWATs under development include the WindTamer from AristaPower, WindCube, Innowind and Enflo turbines.
AxSTREAM is a software suite designed by SoftInWay Inc. for the conceptual design of turbines and compressors and also thermodynamic calculations of existing turbomachinery on-design and off-design operation. The application area of the AxSTREAM software suite covers the design and redesign of turbomachinery, and educational fields.
The Kline–Fogleman airfoil or KF airfoil is a simple airfoil design with single or multiple steps along the length of the wing. It was originally devised in the 1960s for paper airplanes.
XFOIL is an interactive program for the design and analysis of subsonic isolated airfoils. Given the coordinates specifying the shape of a 2D airfoil, Reynolds and Mach numbers, XFOIL can calculate the pressure distribution on the airfoil and hence lift and drag characteristics. The program also allows inverse design - it will vary an airfoil shape to achieve the desired parameters. It is released under the GNU GPL.
ModelCenter, developed by Phoenix Integration, is a software package that aids in the design and optimization of systems. It enables users to conduct trade studies, as well as optimize designs. It interfaces with other popular modeling tools, including Systems Tool Kit, PTC Integrity Modeler, IBM Rhapsody, No Magic, Matlab, Nastran, Microsoft Excel, and Wolfram SystemModeler. ModelCenter also has tools to enable collaboration among design team members.
A variable speed wind turbine is one which is specifically designed to operate over a wide range of rotor speeds. It is in direct contrast to fixed speed wind turbine where the rotor speed is approximately constant. The reason to vary the rotor speed is to capture the maximum aerodynamic power in the wind, as the wind speed varies. The aerodynamic efficiency, or coefficient of power, for a fixed blade pitch angle is obtained by operating the wind turbine at the optimal tip-speed ratio as shown in the following graph.
A cyclorotor, cycloidal rotor, cycloidal propeller or cyclogiro, is a fluid propulsion device that converts shaft power into the acceleration of a fluid using a rotating axis perpendicular to the direction of fluid motion. It uses several blades with a spanwise axis parallel to the axis of rotation and perpendicular to the direction of fluid motion. These blades are cyclically pitched twice per revolution to produce force in any direction normal to the axis of rotation. Cyclorotors are used for propulsion, lift, and control on air and water vehicles. An aircraft using cyclorotors as the primary source of lift, propulsion, and control is known as a cyclogyro or cyclocopter. A unique aspect is that it can change the magnitude and direction of thrust without the need of tilting any aircraft structures. The patented application, used on ships with particular actuation mechanisms both mechanical or hydraulic, is named after German company Voith Turbo.
The pitch bearing, also named blade bearing, is a component of modern wind turbines which connect the rotor hub and the rotor blade. The bearing allows the required oscillation to control the loads and power of the wind turbine. The pitch system brings the blade to the desired position by adapting the aerodynamic angle of attack. The pitch system is also used for emergency breaks of the turbine system.
A vertical-axis wind turbine (VAWT) is a type of wind turbine where the main rotor shaft is set transverse to the wind while the main components are located at the base of the turbine. This arrangement allows the generator and gearbox to be located close to the ground, facilitating service and repair. VAWTs do not need to be pointed into the wind, which removes the need for wind-sensing and orientation mechanisms. Major drawbacks for the early designs included the significant torque ripple during each revolution, and the large bending moments on the blades. Later designs addressed the torque ripple by sweeping the blades helically. Savonius vertical-axis wind turbines (VAWT) are not widespread, but their simplicity and better performance in disturbed flow-fields, compared to small horizontal-axis wind turbines (HAWT) make them a good alternative for distributed generation devices in an urban environment.
