scholarly journals Dependence of Power Characteristics on Savonius Rotor Segmentation

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2912
Author(s):  
Krzysztof Doerffer ◽  
Janusz Telega ◽  
Piotr Doerffer ◽  
Paulina Hercel ◽  
Andrzej Tomporowski
Keyword(s):  
High Wind ◽  
Horizontal Axis Wind Turbine ◽  
Savonius Rotor ◽  
Power Characteristics ◽  
Wind Speeds ◽  
Single Segment ◽  
High Elongation ◽  
Low Wind Speeds ◽  
Number Of Segments ◽  
Rotor Type

Savonius rotors are large and heavy because they use drag force for propulsion. This leads to a larger investment in comparison to horizontal axis wind turbine (HAWT) rotors using lift forces. A simple construction of the Savonius rotor is preferred to reduce the production effort. Therefore, it is proposed here to use single-segment rotors of high elongation. Nevertheless, this rotor type must be compared with a multi-segment rotor to prove that the simplification does not deteriorate the effectiveness. The number of segments affects the aerodynamic performance of the rotor, however, the results shown in the literature are inconsistent. The paper presents a new observation that the relation between the effectiveness of single- and multi-segment rotors depends on the wind velocity. A single-segment rotor becomes significantly more effective than a four-segment rotor at low wind speeds. At high wind speeds, the effectiveness of both rotors becomes similar.

scholarly journals Canard optimization for enhancing the performance of small horizontal axis wind turbine at low wind speeds

2020 ◽  
Vol 37 ◽  
pp. 63-71
Author(s):  
Yui-Chuin Shiah ◽  
Chia Hsiang Chang ◽  
Yu-Jen Chen ◽  
Ankam Vinod Kumar Reddy
Keyword(s):  
Wind Turbine ◽  
Urban Areas ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Peak Performance ◽  
Small Scale ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Optimum Parameters ◽  
Low Wind Speeds

ABSTRACT Generally, the environmental wind speeds in urban areas are relatively low due to clustered buildings. At low wind speeds, an aerodynamic stall occurs near the blade roots of a horizontal axis wind turbine (HAWT), leading to decay of the power coefficient. The research targets to design canards with optimal parameters for a small-scale HAWT system operated at variable rotational speeds. The design was to enhance the performance by delaying the aerodynamic stall near blade roots of the HAWT to be operated at low wind speeds. For the optimal design of canards, flow fields of the sample blades with and without canards were both simulated and compared with the experimental data. With the verification of our simulations, Taguchi analyses were performed to seek the optimum parameters of canards. This study revealed that the peak performance of the optimized canard system operated at 540 rpm might be improved by ∼35%.

Performance Evaluation of New Designs of Wind Towers

2002 ◽  
Author(s):  
Mehdi N. Bahadori ◽  
Amir R. Pakzad
Keyword(s):  
Performance Evaluation ◽  
Natural Ventilation ◽  
Evaporative Cooling ◽  
Ambient Air ◽  
Passive Cooling ◽  
High Wind ◽  
Flow Rates ◽  
Wind Speeds ◽  
Low Wind Speeds

Wind towers are architectural designs employed for natural ventilation and passive cooling of buildings. In this study, it is shown that the performance of these towers can be improved appreciably by incorporating evaporative cooling in them. Two designs, called wetted columns and wetted surfaces, were employed, and their performances were evaluated and compared with those of the conventional towers. It is found that both designs can deliver air to the building they serve at higher flow rates and at temperatures very near the ambient air wet-bulb temperatures. In general, the wind tower with wetted columns performs better in areas with relatively high wind speeds, whereas the designs with wetted surfaces performs better in areas with no winds, or with very low wind speeds.

scholarly journals Assessment of scale of hazards due to pool fire for a fossil fired power plant in India

MAUSAM ◽  
2021 ◽  
Vol 60 (2) ◽  
pp. 197-210
Author(s):  
ARUN KUMAR ◽  
S. K. DASH ◽  
S. K. DHAKA
Keyword(s):  
Wind Speed ◽  
Power Plant ◽  
Radial Distance ◽  
High Wind ◽  
Human Settlement ◽  
Wind Speeds ◽  
Late Night ◽  
Hazardous Condition ◽  
Low Wind Speeds ◽  
Lethal Doses

Hazards for a fossil fired power plant located at   coastal Gujarat in India have been assessed.  The trajectory and spread of the plume from tanks of fossil fired power plant were predicted using existing models named Carter, Mills, Briggs and Zonato during winter and summer seasons with low and high wind speeds observed in day and night hours. Results show that wide areas of habitation and human settlement to the northeast of the site may be potentially under hazards due to southwesterly and southerly winds during summer. Plume heights and widths are found high in the morning hours or late night when wind speeds are low. As wind speed increases around noon, low plume heights and widths are obtained.   Length scales become low at low wind speeds and vice-versa. Lethal doses of thermal radiation beyond radial distance of 70 m are within the tolerable limit under hazardous condition.

Numerical Simulations of the Aerodynamics of Circulation Control Wind Turbines Under Yawed Flow Conditions

2010 ◽  
Author(s):  
Lakshmi N. Sankar ◽  
Chanin Tongchitpakdee ◽  
Mina Zaki ◽  
Robert Englar
Keyword(s):  
Wind Turbine ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Turbine Rotor ◽  
Circulation Control ◽  
Horizontal Axis Wind Turbine ◽  
Flow Solver ◽  
Wind Speeds ◽  
Low Wind Speeds ◽  
Nrel Phase Vi

The aerodynamic performance of a wind turbine rotor equipped with circulation control technology is investigated using a three-dimensional unsteady viscous flow analysis. The National Renewable Energy Laboratory (NREL) Phase VI horizontal axis wind turbine (HAWT) is chosen as the baseline configuration. Experimental data for the baseline case is used to validate the flow solver, prior to its use in exploring these concepts. Steady and pulsed Coanda jet calculations have been performed for axial and yawed flows at several wind conditions. Results presented include radial distribution of the normal and tangential forces at selected radial locations, shaft torque, and root flap bending moments. At low wind speeds where the flow is fully attached, it is found that steady and pulsed Coanda jets at the trailing edge are both effective at increasing circulation resulting in an increase of lift and the chordwise thrust force. This leads to an increased amount of net power compared to the baseline configuration for moderate blowing coefficients. Preliminary calculations are also shown to demonstrate how Coanda jets may be used as jet spoilers to alleviate structural loads under extreme wind conditions.

scholarly journals CFD Comparative Study on Bended and 2D Airfoils on HAWT Performance

2021 ◽  
Vol 2128 (1) ◽  
pp. 012031
Author(s):  
Ahmed H S Yassin ◽  
Sameh M Shabaan ◽  
Amany Khaled
Keyword(s):  
Aerodynamic Characteristics ◽  
Power Coefficient ◽  
Horizontal Axis Wind Turbine ◽  
Circular Section ◽  
Design Point ◽  
Wind Speeds ◽  
Turbine Efficiency ◽  
Rotating Blade ◽  
Low Wind Speeds ◽  
2D Airfoil

Abstract The design of a conventional horizontal axis wind turbine (HAWT) is based on the aerodynamic characteristics of a two-dimensional (2D) airfoil. The rotational motion and the consequent aerodynamic effects, of HAWT’s rotor, do not guarantee an optimal design point that matches the 2D airfoil characteristics. The present work studies the diversion of the flow due to the spanwise velocity component in a rotating reference frame. It suggests that a slight deviation in the flow away from the chordwise direction could alternate the characteristics of the airfoil profile. A bended profile with a circular arc was extracted from a baseline rotating blade, flattened, and modelled against the 2D S826 airfoil. The results show a substantial discrepancy in the airfoil characteristics which could influence the turbine efficiency. Therefore, it suggests using a pre-bended airfoil (3D) while modeling the blade, so the circular section will match the correct airfoil coordinates. The proposed bended-profile version was modeled against the baseline blade. This novel blade shows an augmentation in the power coefficient up to 5.4% starting from the design point to high tip speed ratios (TSR) and low wind speeds.

scholarly journals Design and Fabrication of Multi-Rotor Horizontal Axis Wind Turbine

2019 ◽  
Vol 8 (6) ◽  
pp. 3500-3504 ◽  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Poor Performance ◽  
Small Scale ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Start Up ◽  
Overall Performance ◽  
Low Wind Speeds ◽  
The Cost

Wind is an endless resource which is abundantly found in nature. Harnessing wind energy for producing electricity is one of the ways for buildings for a sustainable future. Small-scale wind turbines could be a reliable energy source for usage in homes and in autonomous applications in locations that are far away from the grid power. Small wind turbines operating at low wind speeds regularly face the problem of poor performance due to small rotor size. To increase the power production additional wind turbines are installed. This increases the overall cost of the project. To reduce the cost and to improve the efficiency, multiple rotors are connected through a single shaft to the fixed single generator. The Implementation of this design permits start up at lower wind speeds, increasing the start-up torque and thus improving the overall performance of the turbine. This paper elaborates the design and fabrication of such a wind turbine. [1] [2] [3]

Basic Design and Blade Structural Analysis of a Small Horizontal-Axis Wind Turbine for Low Wind Speeds

2020 ◽  
Author(s):  
A. R. Krishnanunni ◽  
N. Datta ◽  
H. S. Chambhare ◽  
D. Swaroop
Keyword(s):  
Structural Analysis ◽  
Wind Turbine ◽  
Horizontal Axis ◽  
Weather Data ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Basic Design ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Low Wind Speeds

Abstract The basic design and blade structural analysis of a 250 W rooftop-mounted horizontal-axis wind turbine for low wind speeds is presented. A simplified non-dimensional design is first undertaken to optimize the aerodynamic performance. The non-dimensional power curve vs. the design tip speed ratio is computed with the open-source wind turbine design software QBlade. SD7062 airfoil is chosen for the blade section; and its aerodynamic efficiency is obtained for various angles of attack using XFLR5. The design process also gives the optimal chord length and pitch distribution, leading to the blade geometry. The 22-month weather data at the site has been analyzed to obtain the best-fit Weibull distribution. The blade sizing is based on the maximum power coefficient before the stall regulation happens. An attempt is made to enhance the power capture by using a concentrator, whose aerodynamic efficacy is analyzed. The blades are fabricated from Glass Fiber Reinforced Plastic, which reduces both weight and cost. The configuration for the laminate is finalized after several bending and tensile tests of five distinct GFRP samples. This is followed by the structural analysis of the blade. The root stresses and tip deflection are analyzed for extreme-wind conditions, along with the free vibration frequencies.

scholarly journals Geometry Design Optimization of a Wind Turbine Blade Considering Effects on Aerodynamic Performance by Linearization

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2320 ◽  
Author(s):  
Kyoungboo Yang
Keyword(s):  
Wind Turbine ◽  
Design Optimization ◽  
Turbine Blade ◽  
Aerodynamic Performance ◽  
Wind Turbine Blade ◽  
High Wind ◽  
Aerodynamic Efficiency ◽  
Wind Speeds ◽  
Low Wind Speeds ◽  
Blade Geometry

For a wind turbine to extract as much energy as possible from the wind, blade geometry optimization to maximize the aerodynamic performance is important. Blade design optimization includes linearizing the blade chord and twist distribution for practical manufacturing. As blade linearization changes the blade geometry, it also affects the aerodynamic performance and load characteristics of the wind turbine rotor. Therefore, it is necessary to understand the effects of the design parameters used in linearization. In this study, the effects of these parameters on the aerodynamic performance of a wind turbine blade were examined. In addition, an optimization algorithm for linearization and an objective function that applies multiple tip speed ratios to optimize the aerodynamic efficiency were developed. The analysis revealed that increasing the chord length and chord profile slope improves the aerodynamic efficiency at low wind speeds but lowers it at high wind speeds, and that the twist profile mainly affects the behaviour at low wind speeds, while its effect on the aerodynamic performance at high wind speeds is not significant. When the blade geometry was optimized by applying the linearization parameter ranges obtained from the analysis, blade geometry with improved aerodynamic efficiency at all wind speeds below the rated wind speed was derived.

Investigation of multi rotor small horizontal axis wind turbine at low wind speeds

2020 ◽  
Author(s):  
Manoj Kumar Chaudhary ◽  
S. Prakash ◽  
Tejas Hulawale ◽  
Aditya Shekhar ◽  
Prabhakar Gavade ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Horizontal Axis ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Low Wind Speeds

Oscillating-wing unit for power generation

2018 ◽  
Vol 233 (4) ◽  
pp. 510-529
Author(s):  
Tianshu Liu ◽  
RS Vewen Ramasamy ◽  
Ryne Radermacher ◽  
William Liou ◽  
David Moussa Salazar
Keyword(s):  
Theoretical Analysis ◽  
Power Efficiency ◽  
Power Converter ◽  
Horizontal Axis ◽  
Computational Simulations ◽  
Dynamical Models ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Horizontal Axis Wind Turbines ◽  
Low Wind Speeds

This paper describes an exploratory study of a nonconventional wind power converter with a pair of oscillating wings, which is called an oscillating-wing unit. The working principles of the oscillating-wing unit are described, including the aerodynamic models, kinematical, and dynamical models. The performance of the oscillating-wing unit is evaluated through computational simulations and the power scaling in comparison with conventional horizontal-axis wind turbines. Then, a model oscillating-wing unit is designed, built, and tested in a wind tunnel to examine the feasibility of the oscillating-wing unit in extraction of the wind energy in comparison with the theoretical analysis. The theoretical analysis and experimental data indicate that the oscillating-wing unit has the power efficiency comparable to the conventional horizontal axis wind turbine and it can operate at low wind speeds.

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