scholarly journals ANALYSIS OF AERODYNAMIC PARAMETERS AND ENERGY EFFICIENCY OF VERTICAL AXIS WIND TURBINES

2018 ◽  
pp. 76-84
Author(s):  
Roman Albertovich Ilyin ◽  
Nickolai Dmitrievich Shishkin
Keyword(s):  
Energy Efficiency ◽  
Wind Turbines ◽  
Power Factor ◽  
Vertical Axis ◽  
Relative Width ◽  
Savonius Rotor ◽  
Vertical Axis Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
Aerodynamic Parameters ◽  
Resistance Forces

Analysis of aerodynamics and energy efficiency made it possible to estimate power factors of the most effective up-to-date vertical axis wind turbines. Resistance forces in the traverse flow are so great that they can result in reduction of a power factor from 0.56 to 0.28, i.e. in 2 times. With an increase of angle of the blades placing from 0º to 4º, the power factor increased from 0.40 to 0.61, i. e. in 1,5 times. Optimization of geometric parameters and improvement of generating lines of the blades can increase efficiency of Н-Darier rotor up to 0.72, which exceeds the maximum possible value for horizontal axis wind turbines (0.45). With increasing relative width of the semicylindrical blade from 0.1 to 0.5 and increasing the number of blades from 2 to 6, the power factor of Savonius rotor raises from 0.018 to 0.226. To reduce energy losses in Savonius rotor it is possible to use inclined generators and end elements of blades of various shapes.

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.

scholarly journals Design and Testing of a LUT Airfoil for Straight-Bladed Vertical Axis Wind Turbines

2018 ◽  
Vol 8 (11) ◽  
pp. 2266 ◽  
Author(s):  
Shoutu Li ◽  
Ye Li ◽  
Congxin Yang ◽  
Xuyao Zhang ◽  
Qing Wang ◽  
...  
Keyword(s):  
Wind Turbines ◽  
Lift Coefficient ◽  
Pressure Coefficient ◽  
Vertical Axis ◽  
Reynolds Numbers ◽  
Optimization Method ◽  
Geometrical Parameters ◽  
Vertical Axis Wind Turbines ◽  
University Of Technology ◽  
Horizontal Axis Wind Turbines

The airfoil plays an important role in improving the performance of wind turbines. However, there is less research dedicated to the airfoils for Vertical Axis Wind Turbines (VAWTs) compared to the research on Horizontal Axis Wind Turbines (HAWTs). With the objective of maximizing the aerodynamic performance of the airfoil by optimizing its geometrical parameters and by considering the law of motion of VAWTs, a new airfoil, designated the LUT airfoil (Lanzhou University of Technology), was designed for lift-driven VAWTs by employing the sequential quadratic programming optimization method. Afterwards, the pressure on the surface of the airfoil and the flow velocity were measured in steady conditions by employing wind tunnel experiments and particle image velocimetry technology. Then, the distribution of the pressure coefficient and aerodynamic loads were analyzed for the LUT airfoil under free transition. The results show that the LUT airfoil has a moderate thickness (20.77%) and moderate camber (1.11%). Moreover, compared to the airfoils commonly used for VAWTs, the LUT airfoil, with a wide drag bucket and gentle stall performance, achieves a higher maximum lift coefficient and lift–drag ratios at the Reynolds numbers 3 × 105 and 5 × 105.

STATE OF THE ART OF SMALL WIND ENERGY ANALYSING DIFFERENT CONTROLS

10.6036/10376 ◽  
2022 ◽  
Vol 97 (1) ◽  
pp. 11-11
Author(s):  
MARLON GALLO TORRES ◽  
ENEKO MOLA SANZ ◽  
IGNACIO MUGURUZA FERNANDEZ DE VALDERRAMA ◽  
AITZOL UGARTEMENDIA ITURRIZAR ◽  
GONZALO ABAD BIAIN ◽  
...  
Keyword(s):  
Wind Turbines ◽  
State Of The Art ◽  
Vertical Axis ◽  
Energy Conversion Efficiency ◽  
Horizontal Axis ◽  
Prevailing Wind ◽  
Vertical Axis Wind Turbines ◽  
Axis Of Rotation ◽  
Horizontal Axis Wind Turbines ◽  
Installation Cost

There are two wind turbine topologies according to the axis of rotation: horizontal axis, "Horizontal Axis Wind Turbines" (HAWT) and vertical axis, "Vertical Axis Wind Turbines" (VAWT) [2]. HAWT turbines are used for high power generation as they have a higher energy conversion efficiency [2]. However, VAWTs are used in mini wind applications because they do not need to be oriented to the prevailing wind and have lower installation cost.

scholarly journals Recent Development in the Design of Wind Deflectors for Vertical Axis Wind Turbine: A Review

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5140
Author(s):  
Altaf Hussain Rajpar ◽  
Imran Ali ◽  
Ahmad E. Eladwi ◽  
Mohamed Bashir Ali Bashir
Keyword(s):  
Wind Turbines ◽  
Vertical Axis ◽  
Optimization Techniques ◽  
Rotor Blades ◽  
Power Coefficient ◽  
Potential Contribution ◽  
Vertical Axis Wind Turbine ◽  
Vertical Axis Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
Network Costs

Developments in the design of wind turbines with augmentation are advancing around the globe with the goal of generating electricity close to the user in built-up areas. This is certain to help lessen the power generation load as well as distribution and transmission network costs by reducing the distance between the user and the power source. The main objectives driving the development and advancement of vertical-axis wind turbines are increasing the power coefficient and the torque coefficient by optimizing the upstream wind striking on the rotor blades. Unlike horizontal-axis wind turbines, vertical axis turbines generate not only positive torque but also negative torque during operation. The negative torque generated by the returning blade is a key issue for vertical-axis wind turbines (VAWTs) that is counterproductive. Installation of wind deflectors for flow augmentation helps to reduce the negative torque generated by the returning blades as well as enhance the positive torque by creating a diversion in the upstream wind towards the forwarding blade during operation. This paper reviews various designs, experiments, and CFD simulations of wind deflectors reported to date. Optimization techniques for VAWTs incorporating wind deflectors are discussed in detail. The main focus of the review was on the installation position and orientation of the deflectors and their potential contribution to increasing the power coefficient. Topics for future study are suggested in the conclusion section of the paper.

The Use of Environmentally Friendly Vertical-Axis Wind Power Plants for Nature Reserves and National Parks in Southern Russia

2019 ◽  
Vol 23 (11) ◽  
pp. 43-49
Author(s):  
N.D. Shishkin ◽  
R.A. Ilyin ◽  
D.I. Atdaev
Keyword(s):  
Wind Power ◽  
National Parks ◽  
Wind Turbines ◽  
Power Factor ◽  
Power Plants ◽  
Experimental Studies ◽  
Vertical Axis ◽  
Wind Power Plants ◽  
Vertical Axis Wind Turbines ◽  
Southern Russia

The efficiency of using original highly efficient vertical-axis wind turbines (VA wind turbines) based on N-Darya-Savonius combined rotors (KR) is substantiated for the national parks of southern Russia. Based on experimental studies, the power factor of the original combined rotor with blades having zigzag flaps was first obtained. The maximum values of the power factor of the CR reaches CP = 0.6 exceeding theoretically possible values for horizontal-axis wind power plants CP = 0.59. When working in a wind turbine, there are no emissions of pollutants into the atmosphere, oxygen consumption, thermal pollution, generation of infrasound and noise. VA wind turbines with a power of 1–10 kW, it is advisable to apply for the generation of electric and thermal energy in reserves and national parks.

Experimental Analysis of a 20° Twist Helical Savonius Rotor at Different Overlap Conditions

2014 ◽  
Vol 592-594 ◽  
pp. 1060-1064 ◽  
Author(s):  
Bachu Deb ◽  
Rajat Gupta ◽  
R. D. Misra
Keyword(s):  
Wind Turbines ◽  
Experimental Analysis ◽  
Twist Angle ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Savonius Rotor ◽  
Vertical Axis Wind Turbines ◽  
Torque Coefficient ◽  
Overlap Ratio ◽  
Starting Characteristics

Wind power is a major source of sustainable energy and can be harvested using both horizontal and vertical axis wind turbines. Vertical axis wind turbines (VAWTs) accrue more popularity due to its self-starting characteristics and Omni directional in nature. Out of which Savonius rotor is the most popular drag-based VAWT which is having lower efficiencies but having good self-starting characteristics. In order to improve the performance, helix in the tip of the blade is targeted which reduces the negative torque coefficient of the rotor thereby could improve the performance of the rotor. Therefore, in this paper the power coefficients of a two-bucket helical Savonius rotor at different overlap ratios (from 0.0% to 19.76%) with helix twist angle of 20° are investigated experimentally. The investigations mainly concentrate to find out the optimum overlap ratio which is responsible for generation of maximum aerodynamic power. It is seen from the results that the power coefficient of the rotor increases with the increase in overlap ratio up to a certain limit, and further increase of the same decreases the power coefficients. The maximum power coefficient Cp of 0.289 is obtained at an optimum overlap ratio of 12.76 %.

Experimental Investigation of Overlap and Blockage Effects on Three-Bucket Savonius Rotors

2007 ◽  
Vol 31 (5) ◽  
pp. 363-368 ◽  
Author(s):  
A. Biswas ◽  
R. Gupta ◽  
K.K. Sharma
Keyword(s):  
Wind Turbines ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Experimental Investigations ◽  
Small Scale ◽  
Correction Factors ◽  
Vertical Axis Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
Blockage Correction ◽  
Model Rotor

Savonius vertical axis wind turbines (VAWT) have advantages over horizontal axis wind turbines (HAWT), such as simple construction, acceptance of wind from any direction without orientation, self-starting, inexpensive etc. These advantages make it a viable proposition for small-scale applications in developing countries. In spite of the above advantages, VAWT are not gaining popularity mainly because of their poor efficiency. Hence, a three-bucket Savonius model rotor, having 8 cm bucket diameter and 20 cm height, was designed, fabricated, and tested in a sub-sonic wind tunnel. Provisions for variations of ‘blade’ overlap were included. Experiments were conducted for overlap conditions in the range of 16% to 35%. From the experimental investigations, power-coefficients (Cp) were calculated with and without blockage correction factors for tunnel interference. In both analyses, the power-coefficient increased if there was overlap, with an optimum value at 20% overlap of 47% without blockage correction, and 38% with blockage correction.

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