Wind tunnel testing and numerical simulation on aerodynamic performance of a three-bladed Savonius wind turbine (original) (raw)
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Numerical Investigations on Aerodynamic Characteristics of Savonius Wind Turbine
In This Paper Objective Is To Investigate The Aerodynamic Performance Of Savonius Wind Turbine. Wind Tunnel Investigation Was Carried Out To Find The Aerodynamic Characteristics Like, Drag Coefficient, Torque Coefficient, And Power Coefficient Of Three Blade Savonius Wind Turbine Rotor Models With And Without Overlap Ratio (Ratio Of Overlap Distance Between Two Adjacent Blades And Rotor Diameter ,Or = A/D) At Various Reynolds Numbers. Numerical Investigation Was Acarried Out To Find Those Aerodynamic Characteristics. For Numerical Investigation, Commercial Computational Fluid Dynamic (Cfd) Software Fluent Were Used. Afterwards Those Two Results Were Compared For Verification. The Results From The Experimental Part Of The Research Show A Significant Effect Of Overlap Ratio And Reynolds Number On The Improvement Of Aerodynamic Performance Of The Savonius Wind Turbine. At Higher Reynolds Number Turbine Model Without Overlap Ratio Gives Better Aerodynamic Coefficients And At Lower Reynolds Number Model With Moderate Overlap Ratio Gives Better Results.
Performance Analysis of a Combined Blade Savonius Wind Turbines
International Journal of Fluid Machinery and Systems, 2017
The Savonius wind turbine has a lower performance than other types of wind turbines which may attract more study focus on this turbine. This study aimed to improve wind turbine performance by combining a conventional blade with an elliptical blade into a combined blade rotor. The analysis was performed on three blade models in computational fluid dynamics (CFD) using ANSYS_Fluent Release 14.5. Then the results were verified experimentally using an open wind tunnel system. The results of the numerical simulation were similar to the experimental and showed that the combined blade rotor has better dragging flow and overlap flow than the conventional and elliptical blade. Experimental verification showed that the combined blade was to increase the maximum coefficient of power (Cp max.) by 11% of the conventional blade and to 5.5% of the elliptical blade.
Research & Reviews: Journal of Engineering and Technology, 2012
In this paper, experimental investigations are carried out to study the internal overlap ratios effect on the performance of a Savonius wind rotor at different Reynolds numbers. To do this, an open wind tunnel has been designed and realized in Laboratory of Electro-Mechanic Systems at National School of Engineers of Sfax. This involved also the instrumentation and the necessary equipments for the global characterization of the vertical axis wind turbines. Particularly, this research required the setting up of four mounting characterized by the internal overlap ratios equal to rpi=0, rpi=0.1, rpi=0.2 and rpi=0.3. The overall performance evaluation of the rotor has been based on the power and dynamic torque coefficients
2015
The Savonius wind turbine is a type of vertical axis wind turbine (VAWTs) that is simply composed of two or three arc-type blades which can generate power even under poor wind conditions. A modified Savonius wind turbine with novel blade shapes is introduced with the aim of increasing the power coefficient of the turbine. The effect of blade fullness, which is a main shape parameter of the blade, on the power production of a two-bladed Savonius wind turbine is investigated using transient computational fluid dynamics (CFD). Simulations are based on the Reynolds Averaged Navier-Stokes (RANS) equations with a renormalization group turbulent model. This numerical method is validated with existing experimental data and then utilized to quantify the performance of design variants. Results quantify the relationship between blade fullness and turbine performance with a blade fullness of 1 resulting in the highest coefficient of power, 0.2573. This power coefficient is 10.98% higher than a conventional Savonius turbine.
Experimental Investigation on the Influence of Overlap Ratio on Savonius Turbines Performance
International Journal of Renewable Energy Research, 2018
The paper presents an experimental investigation regarding the influence of the overlap ratio of blades of Savonius wind turbine over its power coefficient and power. Four Savonius wind turbines were fabricated with the overlap ratio of blades of 0.15, 0.20, 0.25 and 0.30. The turbines were subjected to an airflow directed through an opened subsonic wind tunnel. With the obtained results were determined, for each rotor, the variation equations of the rotations per minute depending on wind speed. Afterward, the function type and model of power variation curves depending on wind speed were determined. Following tests, it can be concluded that for wind speeds less than 4 m/s is suitable to be used the Savonius turbine with the overlap ratio of 0.15, while for wind speed that exceeds 4 m/s or areas where the wind has a turbulent character, the Savonius turbine with the overlap ratio of 0.30 is recommended.
A computational study on the aerodynamic performance of modified savonius wind turbine
Results in Engineering, 2021
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Influence of Design Parameters on the Performance of Savonius Wind Turbine
International Journal of Innovative Science and Research Technology, 2022
In this era of technological advancement, the demand for energy requirements is increasing globally. With a limited stock of fossil fuels and the pollution issue related to the burning of these fuels, the world needs to find an alternative of it, which must be cleaner and greener. This is where wind energy comes in and plays a vital role as it is a clean source and has a very promising future in the global energy sector. Savonius turbine is a type of vertical axis wind turbine (VAWT) which is predominantly rotated by the drag force from the wind. It is self starting and can extract wind energy from low wind speeds and is very practical to install it in crowded places due to its compact geometry. This thesis is a review of the previous works presented by different authors. This project aims at discovering the influence of various design and performance parameters (aspect ratio, overlap ratio, tip speed ratio, blade shape, number of rotor blades and number of stages), turbulence models and turbine geometries on the performance of Savonius vertical axis wind turbine. A conventional Savonius vertical axis wind turbine (VAWT) with aspect ratio of 1, overlap ratio of 0.15 and TSR of 0.8 shows the maximum coefficient of power (CP) The performance of conventional rotors can be enhanced by use of helical rotors; multi-staging and other modified blade geometries. Helical rotors with blade twist angle of 90 0 are better performing rotors than the conventional rotors. Modified Bach type rotor with a blade arc angle of 135 0 , aspect ratio of 1.1, overlap ratio of 0.1 and at tip speed ratio (TSR)= 0.8 show the maximum coefficient of power (CP) of 0.30. The results of numerical analyses were compared with that of the experimental data and it is found that for 2-D numerical analyses, realizable k-ɛ turbulence model shows better accuracy of estimation and for 3-D analyses, SST kω turbulence model shows better agreement with the experimental data.
Experimental Study of Combined Blade Savonius Wind Turbine
International Journal of Renewable Energy Research
Many modifications have been made on conventional Savonius wind turbine's rotor blades have been made to improve the performances. The rotor blade modification in this research is a blade combination where the circle-shaped conventional model is combined with the one of a concave elliptical model. The combined blade will not affect the simplicity of construction and cost of manufacture of turbine rotors. The aim is to analyze the influence of the blade combination towards the performance of Savonius turbine. The research includes experimental method using open-jet-type wind tunnel of rotor's prototype with three different blade models of the same dimension. The experiment shows, there are influences of the modification of the rotor blade to the performances of the turbine. The combined blade improves the performances of the power coefficient maximum (Cp max) up to 11 % compared to the conventional blade at the tip speed ratio (TSR) of 0.79.
Renewable Energy, 2012
This paper discusses the influence of the buckets overlap ratio of a Savonius wind rotor on the averaged moment and power coefficients, over complete cycles of operation. The continuity and Reynolds Averaged NaviereStokes (RANS) equations, and the Eddy Viscosity Model keu SST, on its Low-Reynolds approaches, using hybrid near wall treatment; are numerically solved by the commercial software Star-CCM þ . This software is based on Finite Volume Method and computes the pressure and velocity fields of the flow and the forces acting on the rotor buckets. The moment and power coefficients are achieved by integrating the forces coming from the effects of pressure and viscosity of the wind on the device. The influence of the buckets overlap ratio on the moment and power coefficients is checked by changing the geometry of the rotor, keeping the Reynolds number, based on rotor diameter, equal to 433,500. The results obtained for the rotor with zero overlap are in agreement with those obtained experimentally by other authors what indicates that the method can be successfully used for such analysis. The values of the moment and power coefficients obtained as a function of tip speed ratio and the buckets overlap of the rotor indicates that the maximum device performance occurs for buckets overlap ratios with values close to 0.15.
CFD analysis of the effects of multiple semicircular blades on Savonius wind turbine performance
International Journal of Renewable Energy Research, 2020
The goal of this work is to simulate and improve the efficiency of an innovative multiple semicircular-bladed Savonius rotor, which is identified as belonging to the vertical axis wind turbine (VAWT) category. It is characterized as a low speed turbine that is simpler and cheaper to build than traditional turbines. This makes it appropriate for generating mechanical energy in lower wind speed regions, and it can be coupled with solar panels in urban agglomerations. The objective of this paper is to compare the aerodynamic characteristics and power efficiency of four different geometries (two-conventional and two-modified rotors) in order to estimate the most efficient design. The proposed Savonius design comprises multiple semicircular blades added to conventional two-and three-bladed Savonius configurations. The comparison of the efficiency in terms of the torque coefficient (CT) and power coefficient (CP) of the new system configurations with the conventional ones finds that the multiple semicircular two-bladed Savonius rotor is more efficient than others. An average improvement in the power coefficient of 8.43% is observed for the new configuration compared with the others.