Vertical-Axis Wind Turbine Start-Up Modelled with a High-Order Numerical Solver

2015 ◽  
pp. 37-48
Author(s):  
J. M. Rainbird ◽  
E. Ferrer ◽  
J. Peiro ◽  
J. M. R. Graham
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
High Order ◽  
Vertical Axis Wind Turbine ◽  
Start Up ◽  
Numerical Solver

Vortex Analytical Model of a Circulation Controlled Vertical Axis Wind Turbine

2009 ◽  
Author(s):  
Jay P. Wilhelm ◽  
Chad C. Panther ◽  
Franz A. Pertl ◽  
James E. Smith
Keyword(s):  
Wind Turbine ◽  
Analytical Model ◽  
Vertical Axis ◽  
Circulation Control ◽  
Vertical Axis Wind Turbine ◽  
Trailing Edge ◽  
Vortex Interactions ◽  
Vortex Model ◽  
Aspect Ratios ◽  
Start Up

A possible method for modeling a Circulation Controlled - Vertical Axis Wind Turbine (CC-VAWT) is a vortex model, based upon the circulation of a turbine blade. A vortex model works by continuously calculating the circulation strength and location of both free and blade vortices which are shed during rotation. The vortices’ circulation strength and location can then be used to compute a velocity at any point in or around the area of the wind turbine. This model can incorporate blade wake interactions, unsteady flow conditions, and finite aspect ratios. Blade vortex interactions can also be studied by this model to assist designers in the avoidance of adverse turbulent operational regions. Conventional vertical axis wind turbine power production is rated to produce power in an operating wind speed envelope. These turbines, unless designed specifically for low speed operation require rotational start-up assistance. The VAWT blade can be augmented to include circulation control capabilities. Circulation control can prolong the trailing edge separation and can be implemented by using blowing slots located adjacent to a rounded trailing edge surface; the rounded surface of the enhanced blade replaces the sharp trailing edge of a conventional airfoil. Blowing slots of the CC-VAWT blade are located on the top and bottom trailing edges and are site-controlled in multiple sections along the span of the blade. Improvements in the amount of power developed at lower speeds and the elimination or reduction of start-up assistance could be possible with a CC-VAWT. In order to design for a wider speed operating range that takes advantage of circulation control, an analytical model of a CC-VAWT would be helpful. The primary function of the model is to calculate the aerodynamic forces experienced by the CC-VAWT blade during various modes of operation, ultimately leading to performance predictions based on power generation. The model will also serve as a flow visualization tool to gain a better understanding of the effects of circulation control on the development and interactions of vortices within the wake region of the CC-VAWT. This paper will describe the development of a vortex analytical model of a CC-VAWT.

Numerical Investigation of Aerodynamic Performance of a Three-Bladed Vertical Axis Wind Turbine

2010 ◽  
Author(s):  
Alexandrina Untaroiu ◽  
Lydia R. Barker ◽  
Houston G. Wood ◽  
Robert J. Ribando ◽  
Paul E. Allaire
Keyword(s):  
Wind Turbine ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
Operating Speed ◽  
University Of Virginia ◽  
Vertical Axis Wind Turbine ◽  
Start Up ◽  
Ansys Cfx ◽  
Turbine Design ◽  
The University

As a pollution free source of energy, wind is among the most popular and fastest growing forms of electricity generation in the world. Compared to their horizontal axis counterparts, vertical axis wind turbines have lagged considerably in development and implementation. The University of Virginia Rotating Machinery and Controls laboratory has undertaken a systematic review of vertical axis wind turbine design in order to address this research gap, starting with establishment of a methodology for vertical axis wind turbine simulation using ANSYS CFX. A 2D model of a recently published Durham University vertical axis wind turbine was generated. Full transient CFD simulations using the moving mesh capability available in ANSYS-CFX were run from turbine start-up to operating speed and compared with the experimental data in order to validate the technique. A scalable k-ε turbulence model transient CFD simulation has been demonstrated to accurately predict vertical axis wind turbine operating speed within 12% error using a two-dimensional structured mesh in conjunction with a carefully specified series of boundary conditions.

scholarly journals Power Enhancement of a Vertical Axis Wind Turbine Equipped with an Improved Duct

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5780
Author(s):  
Mohammad Hassan Ranjbar ◽  
Behnam Rafiei ◽  
Seyyed Abolfazl Nasrazadani ◽  
Kobra Gharali ◽  
Madjid Soltani ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Flow Characteristics ◽  
Maximum Velocity ◽  
Leading Edge ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Numerical Solver ◽  
Main Components

Efforts to increase the power output of wind turbines include Diffuser Augmented Wind Turbines (DAWT) or a shroud for the rotor of a wind turbine. The selected duct has three main components: a nozzle, a diffuser, and a flange. The combined effect of these components results in enriched upstream velocity for the rotor installed in the throat of the duct. To obtain the maximum velocity in the throat of the duct, the optimum angles of the three parts have been analyzed. A code was developed to allow all the numerical steps including changing the geometries, generating the meshes, and setting up the numerical solver simultaneously. Finally, the optimum geometry of the duct has been established that allows a doubling of the flow velocity. The flow characteristics inside the duct have also been analyzed in detail. An H-Darrieus Vertical Axis Wind Turbine (VAWT) has been simulated inside the optimized duct. The results show that the power coefficient of the DAWT can be enhanced up to 2.9 times. Deep dynamic stall phenomena are captured perfectly. The duct advances the leading-edge vortex generation and delays the vortex separation.

scholarly journals Simplified nonlinear rotational inertia model for the simulation and analysis of the characteristics of an unconventional VAWT type wind turbine with variable pitch

2021 ◽  
pp. 11-22
Author(s):  
David Franco-Martínez ◽  
Jesús García-Barrera ◽  
Jorge Díaz-Salgado ◽  
Oliver M. Huerta-Chávez
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Rotational Inertia ◽  
Vertical Axis Wind Turbine ◽  
Aerodynamic Coefficients ◽  
Stream Tube ◽  
Variable Pitch ◽  
Output Torque ◽  
Start Up ◽  
Inertia Model

This paper shows a double multiple stream tube model coupling to a rotational inertia model. It allows the simulation and analysis of the characteristics of an unconventional vertical-axis wind turbine (VAWT) with Variable Pitch. This implementation permits to employ a stationary response of the wind turbine calculated across the main characteristics of output torque based on experimental aerodynamic coefficients and the Reynolds at each station, can be transformed into a transient response by a simplified non-linear rotational inertia dynamic model to predict the start-up, idle, stabilization and sudden stop of our device.

scholarly journals Modeling, Simulation, Hardware Implementation of a Novel Variable Pitch Control for H-Type Vertical Axis Wind Turbine

2015 ◽  
Vol 66 (5) ◽  
pp. 264-269 ◽  
Author(s):  
Liqun Liu ◽  
Chunxia Liu ◽  
Xuyang Zheng
Keyword(s):  
Wind Turbine ◽  
Control Method ◽  
Vertical Axis ◽  
Utilization Efficiency ◽  
Vertical Axis Wind Turbine ◽  
Variable Pitch ◽  
Pitch Control ◽  
Start Up ◽  
Variable Pitch Control ◽  
Fixed Pitch

Abstract It is well known that the fixed pitch vertical axis wind turbine (FP-VAWT) has some disadvantages such as the low start-up torque and inefficient output efficiency. In this paper, the variable pitch vertical axis wind turbine (VP-VAWT) is analyzed to improve the output characteristics of FP-VAWT by discussing the force of the six blade H type vertical axis wind turbine (VAWT) under the stationary and rotating conditions using built the H-type VAWT model. First, the force of single blade at variable pitch and fixed pitch is analyzed, respectively. Then, the resultant force of six blades at different pitch is gained. Finally, a variable pitch control method based on a six blade H type VP-VAWT is proposed, moreover, the technical analysis and simulation results validate that the variable pitch method can improve the start-up torque of VAWT, and increase the utilization efficiency of wind energy, and reduce the blade oscillation, as comparable with that of FP-VAWT.

Aerodynamic Model of Vertical Axis Wind Turbine with Wind Speed Self-Adapting in Drag-Mode

2011 ◽  
Vol 347-353 ◽  
pp. 340-343 ◽  
Author(s):  
Jian Jun Qu ◽  
Ming Wei Xu ◽  
Yi Mei
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Special Structure ◽  
Vertical Axis Wind Turbine ◽  
Low Wind Speed ◽  
Aerodynamic Model ◽  
Start Up ◽  
Opening And Closing ◽  
Better Than

The structure of vertical axis wind turbine with wind speed-adapting is based on Darrieus straight-bladed turbine. It features that its blades are composed of movable and fixed blades. Through the opening and closing of the movable blades to adapt to the wind speed automatically, the turbine not only can start up in low wind speed, but also realize the conversion from drag-mode to lift-mode. Due to the special structure, the aerodynamic model of this turbine in drag-mode is different from that of Savonius and Darrieus turbine. So in this article, the aerodynamic model of this turbine in drag-mode is established. Then the coefficient of start-up torque is calculated and compared with that of Darrieus straight-bladed turbine which has the same size. The results show that the start-up performance of this turbine is obviously better than that of Darrieus straight-bladed turbine.

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