scholarly journals Study of performance of h-rotor darrieus wind turbines

2021 ◽  
Author(s):  
Sandeep Christy R ◽  
◽  
Kousik S C ◽  
Vishal Subramaniam R ◽  
Santhosh Ram R ◽  
...  
Keyword(s):  
Wind Velocity ◽  
Turbine Blade ◽  
Wind Turbines ◽  
Pitch Angle ◽  
Vertical Axis ◽  
Blade Profile ◽  
Rotor Design ◽  
Wind Velocities ◽  
Major Factors ◽  
Blade Pitch Angle

Vertical Axis Wind Turbines (VAWTs) are mostly manufactured keeping in mind the site and conditions that the wind turbine would face. There is a need to know which type of VAWT would be optimal in the conditions present at the installation site. The major factors involved are blade profile, wind velocity and blade pitch angle. This study is undertaken to study these factors and their effects on influencing the efficiency of the VAWT. A model has been made of a Darrieus VAWT with H-rotor design and is analyzed using CFD. An Iso-surface mesh is made on the model with a cylindrical air-filled domain and a κ-ε turbulence model is applied to study the effects of the wind-and-turbine blade interaction. The domain inlet indicates wind velocity; outlet is set to zero atmospheric gauge pressure and the pressure distribution across the turbine blade wall is measured. The top bottom walls of the domain are not part of the interaction. The study shows that the NACA0012 blade profile fares better than the other profiles across the range of wind velocities. However, it is less efficient with an increase in blade pitch angle for the same value of velocity. NACA0015 blade profile gives good performance when it has a zero pitch angle for intermediate and high wind velocities.

Computational Study of Savonius Wind Turbines

2014 ◽  
Author(s):  
Majid Rashidi ◽  
Jaikrishnan R. Kadambi ◽  
Asmita Chinchore
Keyword(s):  
Turbine Blade ◽  
Wind Turbines ◽  
Computational Study ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Prevailing Wind ◽  
Maximum Change ◽  
Wind Velocities ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

This work presents a computational study of a two-blade and a three-blade Savonius vertical axis wind turbines. The two-blade turbine was considered to be oriented at 0, 45, 90, and 135 degrees in reference to the direction of the prevailing wind. For the three-blade turbine, the orientations taken into account were 0, 30, 60, and 90 degrees in reference to the direction of the prevailing wind. The basic aim of this work was to study how the two designs are different from each other in terms of the forces acting on their blades. The computational simulations considered the turbines to be subjected to constant wind velocities of 5, 10, 20, and 30 m/s. Computational Fluid Dynamics (CFD) analyses were conducted for every case to find out the forces acting on the turbine blades for each orientation. All cases were run using “transition-SST” flow model and the turbine blades were meshed using ‘Quadrilateral Pave’ meshing scheme. Maximum change in pressure on the turbine blade occurs when the two-blade turbine is perpendicular to direction of the prevailing wind, i.e. at 90 degree. On the other hand, when three-blade turbine is at 60 degree orientation, maximum change is pressure occurs on the turbine blade. For the dimensions selected in this study (each blade having a radius of 0.3 m and height of 0.6 m) the maximum net forces on the two-blade turbine was calculated to be 298 N, while this value was 210 N on the three-blade turbine.

Active Blade Pitch Control for Straight Bladed Darrieus Vertical Axis Wind Turbine of New Design

2013 ◽  
Vol 569-570 ◽  
pp. 668-675 ◽  
Author(s):  
P.D. Chougule ◽  
S.R.K. Nielsen ◽  
Biswajit Basu
Keyword(s):  
Wind Speed ◽  
Wind Turbines ◽  
Pitch Angle ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Stream Tube ◽  
Pitch Control ◽  
Low Wind Speed ◽  
Blade Pitch Angle

As Development of smallvertical axis wind turbines (VAWT) for urban use is becoming an interestingtopic both within industry and academia. However, there are few new designs ofvertical axis turbines which are customized for building integration. These aregetting importance because they operate at low rotational speed producing veryless noise during operation, although these are less efficient than HorizontalAxis Wind Turbines (HAWT). The efficiency of a VAWT has been significantlyimproved by H-Darrieus VAWT design based on double airfoil technology asdemonstrated by the authors in a previous publication. Further, it is well knowthat the variation of the blade pitch angle during the rotation improves thepower efficiency. A blade pitch variation is implemented by active blade pitchcontrol, which operates as per wind speed and position of the blade withrespect to the rotor. A double multiple stream tube method is used to determinethe performance of the H-Darrieus VAWT. The power coefficient is compared withthat of a fixed pitch and a variable pitch double airfoil blade VAWT. It isdemonstrated that an improvement in power coefficient by 20% is achieved andthe turbine could start at low wind speed

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.

Wind Turbine Aerodynamic Braking System Analysis Using Chord Wise Spacing

2015 ◽  
Vol 787 ◽  
pp. 217-221 ◽  
Author(s):  
B. Navin Kumar ◽  
K.M. Parammasivam
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Wind Velocity ◽  
Turbine Blade ◽  
Wind Turbines ◽  
Renewable Energy Sources ◽  
Energy Resource ◽  
Braking System ◽  
Extreme Wind ◽  
Wind Potential

Wind energy is one of the most significant renewable energy sources in the world. It is the only promising renewable energy resource that only can satisfy the nation’s energy requirements over the growing demand for electricity. Wind turbines have been installed all over the wind potential areas to generate electricity. The wind turbines are designed to operate at a rated wind velocity. When the wind turbines are exposed to extreme wind velocities such as storm or hurricane, the wind turbine rotates at a higher speed that affects the structural stability of the entire system and may topple the system. Mechanical braking systems and Aerodynamic braking systems have been currently used to control the over speeding of the wind turbine at extreme wind velocity. As a novel approach, it is attempted to control the over speeding of the wind turbine by aerodynamic braking system by providing the chord wise spacing (opening). The turbine blade with chord wise spacing alters the pressure distribution over the turbine blade that brings down the rotational speed of the wind turbine within the allowable limit. In this approach, the over speeding of the wind turbine blades are effectively controlled without affecting the power production. In this paper the different parameters of the chord wise spacing such as position of the spacing, shape of the spacing, width of the spacing and impact on power generation are analyzed and the spacing parameters are experimentally optimized.

scholarly journals A review of H-Darrieus wind turbine aerodynamic research

2019 ◽  
Vol 233 (23-24) ◽  
pp. 7590-7616 ◽  
Author(s):  
Longhuan Du ◽  
Grant Ingram ◽  
Robert G Dominy
Keyword(s):  
Wind Turbine ◽  
Pitch Angle ◽  
Vertical Axis ◽  
Design Parameters ◽  
Blade Profile ◽  
Horizontal Axis Wind Turbine ◽  
Detailed Review ◽  
Main Research ◽  
Vertical Axis Turbine ◽  
Will Self

The H-Darrieus vertical axis turbine is one of the most promising wind energy converters for locations where there are rapid variations of wind direction, such as in the built environment. The most challenging considerations when employing one of these usually small machines are to ensure that they self-start and to maintain and improve their efficiency. However, due to the turbine's rotation about a vertical axis, the aerodynamics of the turbine are more complex than a comparable horizontal axis wind turbine and our knowledge and understanding of these turbines falls remains far from complete. This paper provides a detailed review of past and current studies of the H-Darrieus turbine from the perspective of design parameters including turbine solidity, blade profile, pitch angle, etc. and particular focus is put on the crucial challenge to design a turbine that will self-start. Moreover, this paper summarizes the main research approaches for studying the turbine in order to identify successes and promising areas for future study.

Analysis of Structural Vibrations of Vertical Axis Wind Turbine Blades via Hamilton’s Principle — Part 3: Pitch Angle and Equilibrium State

2021 ◽  
pp. 2150070
Author(s):  
Jianyou Huang ◽  
Chia-Ou Chang ◽  
Chien-Cheng Chang
Keyword(s):  
Exact Solution ◽  
Equilibrium State ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Pitch Angle ◽  
Coupling Effect ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Wind Turbine Blade ◽  
Vertical Axis Wind Turbine

Pitch angle is one of the most important parameters of wind turbine blade. This study is aimed to investigate the effect of the pitch angle on the deformation of a VAWT. Lagrangian mechanics and Euler’s beam theory are used to derive the motion equations of linear structural vibration for straight blade vertical axis wind turbine blade with the pitch angle [Formula: see text]. The complete equations of motion take account of the 4-DOF deformation of flexural–flexural–torsion–extension as well as the material damping. Vibration analysis of generalized displacement about the equilibrium state (GDAES) is carried out with respect to the displacement of the equilibrium state (DOES), which is separated from the motion of vibration. After simplifying the equilibrium equation of 4-DOF into 1-DOF system, the exact solution of displacement [Formula: see text] of the equilibrium state is derived. The correction [Formula: see text] of [Formula: see text] due to the pitch angle and the characteristics of [Formula: see text] with constant linear speed are analyzed. Furthermore, we investigate the coupling effect of lateral bending and axial extension of the blade on [Formula: see text] is analyzed. Finally, the exact solution of [Formula: see text] is verified by the central difference method.

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