The Influence of the Number of Semi-Cycindrical Cups on the Behavior of an Experimental Model of Vertical Axis Wind Turbine at Low Wind Speed and no Load

2020 ◽  
Vol 43 (3) ◽  
pp. 43-53
Author(s):  
Nelu CAZACU ◽  
◽  
◽  
Keyword(s):  
Wind Tunnel ◽  
Experimental Model ◽  
Vertical Axis ◽  
Experimental Models ◽  
Vertical Axis Wind Turbine ◽  
Cross Sectional ◽  
Wind Speeds ◽  
Low Wind Speed ◽  
Cylindrical Cup ◽  
Electrical Loads

The work is based on experiments made in the wind tunnel on experimental models of Savonius type wind turbines with blades in the shape of a semicylindrical cup. The number of blades changes: 2, 3, 4, 5 and 6. The experimental model allows the addition / removal of blades in the form of a semi-cylindrical cup followed by static balancing. The wind tunnel used has the measuring area 0.5 mx0.5 m and the length of 1.25 m and the experimental models have the interception surface at a maximum value of 10% of the cross-sectional area of the wind tunnel (diameter 158 mm and height 158 mm). The experiments were performed at wind speeds between 0...9.7 m/s between peaks and no (mechanical and / or electrical) loads. The results confirm the influence of the number of semi-cylindrical cups on the rotational speed and other factors over experimental model of Savonius type turbines in no load conditions.

scholarly journals Experimental and Numerical Investigation on the Performance of Straight-Bladed Vertical Axis Wind Turbine by Adding Cavities to it Structure

2020 ◽  
Vol 26 (4) ◽  
pp. 64-79
Author(s):  
Ahmed Saadi AlJarakh ◽  
Hussain Yousif Mahmood
Keyword(s):  
Wind Speed ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Wind Speeds ◽  
Low Wind Speed ◽  
Low Performance ◽  
New Policies ◽  
Energy Harnessing

As the prices of the fuel and power had fluctuated many times in the last decade and new policies appeared and signed by most of the world countries to eliminate global warming and environmental impact on the earth surface and humanity exciting, an urgent need appeared to develop the renewable energy harnessing technologies on the short-term and long-term and one of these promising technologies are the vertical axis wind turbines, and mostly the combined types. The purpose of the present work is to combine a cavity type Savonius with straight bladed Darrieus to eliminate the poor self-starting ability for Darrieus type and low performance for Savonius type and for this purpose, a three-bladed Darrieus type with symmetrical S1046 airfoil was tested experimentally and numerically at different wind speeds (4.5 m/s, 8 m/s and 10 m/s) and it showed a poor self-starting ability at low wind speed although its higher performance at high wind speed. However when adding the cavities in two setup configuration and testing it at the same conditions, it was found that when adding the cavities as reversed cups in the core of the turbine, the performance increased and the power coefficient reached a maximum value at 10 m/s wind speed and it was observed to be 0.0914 , but when the solidity increased by adding three cavities, the performance was higher at low wind speed (4.5 m/s) but it tragically decreased at higher wind speed which indicates that the performance depends on the solidity and the turbine configuration. On the other hand, the numerical simulation showed a good match with the experimental results although it under-predicted the performance.

Investigation of Aerodynamic Performance of Helical Shape Vertical-Axis Wind Turbine Models With Various Number of Blades Using Wind Tunnel Testing and Computational Fluid Dynamics

2016 ◽  
Author(s):  
Mosfequr Rahman ◽  
Travis Salyers ◽  
Mahbub Ahmed ◽  
Adel ElShahat ◽  
Valentin Soloiu ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Twist Angle ◽  
Average Power ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Wind Tunnel Testing ◽  
Vertical Axis Wind Turbine ◽  
Wind Speeds ◽  
Tunnel Testing

The demand for wind energy as a renewable source is rising substantially. A growing interest exists in utilizing potential energy conversion applications in areas with less powerful and less consistent wind conditions. In these areas, vertical-axis wind turbines (VAWTs) possess several advantages over the conventional horizontal-axis type. Savonius turbines are drag-based rotors which operate due to a pressure difference between the advancing and retreating blades. These turbines are simpler in design, less expensive to install, independent of wind direction, and more efficient at low wind speeds. In the present study, rotors were designed with semi-circle blades consisting of a helical shape with twist angle of 90 degrees. Helical designs spread the torque applied to the rotor over a complete revolution with the purpose of increasing efficiency. Three models were analyzed with different number of blades including 2, 3, and 4 blade models. Models for testing were designed using the CAD software SolidWorks. The blades were then 3D printed with PLA plastic. A consistent swept area was maintained for each model, and only blade number was varied. Subsonic, open-type wind tunnel testing was used for measuring RPM and reactional torque over a range of wind speeds. For the numerical approach, ANSYS Fluent simulations were used for analyzing aerodynamic performance by utilizing moving reference frame and sliding mesh model techniques. Due to the helical twist, the cross-section of the blades varied in the Y-direction. Because of this, a 3-dimensional and transient method was used for accurately solving torque and power coefficients. It has been found that the highest average power coefficient observed in the study is achieved by the Helical2 model (2-bladed helical design VAWT model), both numerically and experimentally.

scholarly journals Analysis of the Behavior in the Wind Tunnel of an Experimental Model of Savonius with Interlocking Cups with the Classic Ones with 2, 3 and 4 Semi-Cylindrical Cups

2021 ◽  
Vol 44 (1) ◽  
pp. 11-18
Author(s):  
Nelu CAZACU
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Experimental Model ◽  
Experimental Models ◽  
Dead Zones ◽  
Wind Speeds ◽  
Measuring Section ◽  
Formed Channel ◽  
Low Wind Speeds ◽  
Air Passage

The paper is based on experiments conducted on the wind tunnel at low wind speeds (<9.5 m/s), on an experimental model of S-rotor wind turbine type with four blades and a D/H ratio of 1. Semi-cylindrical cups opposite 180 degrees are aerodynamically coupled by overlap and with an air passage gap to equalize the pressures. The formed channel is shaped to allow the same for pairs of blades at 90 degrees. The experimental model has an area of 0.025 m2 which represents 10% of the surface of the measuring section of the wind tunnel (0.25 m2). The behavior of the experimental model was compared with the experimental models of S-rotor with 2, 3 and 4 semi-cylindrical cups, with the same interception surface. The results confirm the better start of the experimental model by reducing dead zones and operating more evenly and stably over a longer range of wind speeds. The results confirm the validity of the proposed concept of interwoven aerodynamic coupling of semi-cylindrical cups.

scholarly journals Proposal of a Nature-Inspired Shape for a Vertical Axis Wind Turbine and Comparison of Its Performance with a Semicircular Blade Profile

2021 ◽  
Vol 11 (13) ◽  
pp. 6198
Author(s):  
Javier Blanco ◽  
Juan de Dios Rodriguez ◽  
Antonio Couce ◽  
Maria Isabel Lamas
Keyword(s):  
Numerical Model ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Experimental Model ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Power Coefficient ◽  
Cfd Model ◽  
Blade Profile ◽  
Vertical Axis Wind Turbine

In order to improve the efficiency of the Savonius type vertical axis wind turbine, the present work analyzes an improvement based on an innovative rotor geometry. The rotor blades are inspired on an organic shape mathematically analyzed, the Fibonacci’s spiral, presented in many nature systems as well as in art. This rotor was analyzed in a wind tunnel and through a CFD model. The power coefficients at different tip speed ratios (TSR) were characterized and compared for the Savonius turbine and two versions using the Fibonacci’s spiral. One of the proposed geometries improves the performance of the Savonius type. Particularly, the optimal configuration lead to an improvement in maximum power coefficient of 14.5% in the numerical model respect to a conventional Savonius turbine and 17.6% in the experimental model.

Wind tunnel and numerical study of a straight-bladed Vertical Axis Wind Turbine in three-dimensional analysis (Part II: For predicting flow field and performance)

Energy ◽  
2016 ◽  
Vol 104 ◽  
pp. 295-307 ◽  
Author(s):  
Qing'an Li ◽  
Takao Maeda ◽  
Yasunari Kamada ◽  
Junsuke Murata ◽  
Toshiaki Kawabata ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
Wind Turbine ◽  
Dimensional Analysis ◽  
Numerical Study ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
And Performance

scholarly journals Conceptual Design and Structure Analysis of Giromill Vertical Axis Wind Turbine under Low Wind Speed

2020 ◽  
Vol 75 (2) ◽  
pp. 11-19
Author(s):  
Mohamed Saiful Firdaus Hussin ◽  
Mohd Fariduddin Mukhtar ◽  
Mohd Zaidi Mohd Tumari ◽  
Nursabillilah Mohd Ali ◽  
Amir Abdullah Muhammad Damanhuri ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Conceptual Design ◽  
Structure Analysis ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Low Wind Speed

scholarly journals Design and Contruction of Vertical Axis Wind Turbine Triple-Stage Savonius Type as the Alternative Wind Power Plant

KnE Energy ◽  
2015 ◽  
Vol 2 (2) ◽  
pp. 172
Author(s):  
Tedy Harsanto ◽  
Haryo Dwi Prananto ◽  
Esmar Budi ◽  
Hadi Nasbey
Keyword(s):  
Wind Speed ◽  
Power Plant ◽  
Wind Turbine ◽  
Wind Power ◽  
Output Power ◽  
Vertical Axis ◽  
Wind Power Plant ◽  
Vertical Axis Wind Turbine ◽  
Low Wind Speed ◽  
Simple Materials

<p>A vertical axis wind turbine triple-stage savonius type has been created by using simple materials to generate electricity for the alternative wind power plant. The objective of this research is to design a simple wind turbine which can operate with low wind speed. The turbine was designed by making three savonius rotors and then varied the structure of angle on the three rotors, 0˚, 90˚ and 120˚. The dimension of the three rotors are created equal with each rotor diameter 35 cm and each rotor height 19 cm. The turbine was tested by using blower as the wind sources. Through the measurements obtained the comparisons of output power, rotation of turbine, and the level of efficiency generated by the three variations. The result showed that the turbine with angle of 120˚ operate most optimally because it is able to produce the highest output power and highest rotation of turbine which is 0.346 Watt and 222.7 RPM. </p><p><strong>Keywords</strong>: Output power; savonius turbine; triple-stage; the structure of angle</p>

Aerodynamic Analysis for Camber Effect in Vertical Wind Turbine System

2011 ◽  
Author(s):  
Jinwook Kim ◽  
Dohyung Lee ◽  
Junhee Han ◽  
Sangwoo Kim
Keyword(s):  
Numerical Simulation ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Low Wind Speed ◽  
Wind Turbine System ◽  
Physical Features ◽  
The Ideal

The Vertical Axis Wind Turbine (VAWT) has advantages over Horizontal Axis Wind Turbine (HAWT) that it allows less chance to be degraded independent of wind direction and turbine can be operated even at the low wind speed. The objective of this study is to analyze aerodynamics of the VAWT airfoil and investigate the ideal shape of airfoil, more specifically cambers. The analysis of aerodynamic characteristics with various cambers has been performed using numerical simulation with CFD software. As the numerical simulation discloses local physical features around wind turbine, aerodynamic performance such as lift, drag and torque are computed for single airfoil rotation and multiple airfoil rotation cases. Through this study more effective airfoil shape is suggested based vortex-airfoil interaction studies.

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