Experimental and Numerical Investigations on Aerodynamic Characteristics of Savonius Wind Turbine with Various Overlap Ratios

Savonius wind turbine is the simplest type of vertical axis rotor that has a relatively low efficiency. Operation of the Savonius wind turbine is based on the difference of the drag force on its semi-spherical blades, depending on whether the wind is striking the convex or the concave part of the blades. This turbine is being used in various countries around the world due to the simplistic design, cheap technology for construction, and a good starting torque independent of wind direction at low wind speeds. Due to its simple design and low construction cost, this rotor is mainly used for water pumping as well as wind power on small scale. The main goal of this current research 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 also carried out to find those aerodynamic characteristics. For numerical investigation, commercial computational fluid dynamic (CFD) software GAMBIT and FLUENT were used. Afterwards those two results were compared for verification. Three different models with different overlap ratio were designed and fabricated for the current study to find the effect of overlap ratios. 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

Leadership competency

Leadership is a procedure by which an individual impacts other to achieve a target and coordinates the association such that makes it increasingly firm and cognizant (Sharma & Jain, 2013). This definition is like Northouse's (2007) definition — Leadership is a procedure whereby an individual impact a gathering of people to accomplish a shared objective

Numerical Investigation and Improvement of Aerodynamic Performance of Savonius Wind Turbine

Higher demand for energy has lead to increase in the consumption of conventional energy which has become more expensive and scarce. There is the need to generate power from renewable sources to reduce the demand for fossil fuels and growing concern due to increase in the effects of climate change, such as global warming and acid rain generated by extensive and deliberate use of fossil fuels in the electric generating plants and transport system. In this work, the aerodynamic characteristics of Savonius wind turbine were investigated numerically by varying the rotor configuration (semi-circular and segment of circle) and overlap ratio so as to obtain the optimum design configuration which could give better performance of Savonius rotor. Comparison between the static torque coefficient at different overlap ratios of 0%, 20%, and 40% for the two configurations were studied using Solidworks CFD software. The flow around the rotor with overlap ratio variation was analyzed with the help of velocity, pressure contours and static torque coefficient equation of the rotor. It was observed from the analysis that the overlap of 20% was the optimum overlap condition at which pressure, velocity differences and coefficient of static torque across the rotor were the highest for both configurations and that segment of a circle produced the highest characteristics for better performance. Keywords: Overlap ratio, aerodynamic, Savonius, Static torque coefficient, rotor configuration

State of the Art in the Optimisation of Wind Turbine Performance Using CFD

Wind energy has received increasing attention in recent years due to its sustainability and geographically wide availability. The efficiency of wind energy utilisation highly depends on the performance of wind turbines, which convert the kinetic energy in wind into electrical energy. In order to optimise wind turbine performance and reduce the cost of next-generation wind turbines, it is crucial to have a view of the state of the art in the key aspects on the performance optimisation of wind turbines using Computational Fluid Dynamics (CFD), which has attracted enormous interest in the development of next-generation wind turbines in recent years. This paper presents a comprehensive review of the state-of-the-art progress on optimisation of wind turbine performance using CFD, reviewing the objective functions to judge the performance of wind turbine, CFD approaches applied in the simulation of wind turbines and optimisation algorithms for wind turbine performance. This paper has been written for both researchers new to this research area by summarising underlying theory whilst presenting a comprehensive review on the up-to-date studies, and experts in the field of study by collecting a comprehensive list of related references where the details of computational methods that have been employed lately can be obtained

DESIGN AND ANALYSIS OF 5 KW SAVONIUS ROTOR BLADE

This paper presents the design and analysis of the Savonius rotor blade to generate 5 kW power output. The relevant design parameters and theories were studied in this paper and used to determine related design geometry and requirements of the Savonius rotor blade. The Savonius rotor was designed with the rotor diameter of 3.5 m and the rotor height of 7 m. The 3D model of Savonius rotor blade was created by using SolidWorks software. Computational Fluid Dynamics (CFD) analysis and structural Finite Element Analysis (FEA) are presented in this paper. CFD analysis was performed to obtain the pressure difference between concave and convex region of the blade while FEA was done to obtain the structural response of the blade due to the wind load applied in term of stresses and its displacements

ESFuelCell2011-54173 NUMERICAL ANALYSIS OF A ROOFTOP VERTICAL AXIS WIND TURBINE

ABSTRACT A numerical analysis of a rooftop vertical axis wind turbine (VAWT) for applications in urban area is presented. The numerical simulations were developed to study the flow field through the turbine rotor to analyze the aerodynamic performance characteristics of the device. Three different blade numbers of wind turbine are studied, 2, 3 and 4, respectively. Each one of the models was built in a 3D computational model. The effects generated in the performance of turbines by the numbers of blades are considered. A Sliding Mesh Model (SMM) capability was used to present the dimensionless form of coefficient power and coefficient moment of the wind turbine as a function of the wind velocity and the rotor rotational speed. The numerical study was developed in CFD using FLUENT®. The results show the aerodynamic performance for each configuration of wind turbine rotor. In the cases of Rooftop rotor the power coefficient increases as the blade number increases, while in the case of Savonius rotor the power coefficient decrease as the blades number increases. K eywords: Wind energy, rooftop turbine, vertical axis wind turbine, torque coefficient and power coefficient

Analysis of a nature-inspired shape for a vertical axis wind turbine

[Abstract] Wind energy is gaining special interest worldwide due to the necessity of reducing pollutant emissions and employ renewable resources. Traditionally, horizontal axis wind turbines have been employed but certain situations require vertical axis wind turbines. With a view to improve the efficiency of a vertical axis wind turbine Savonius type, the present work proposes a bioinspired design blade profile relying on the Fibonacci spiral. This shape is repeatedly presented in nature and thus it leads to a bio-inspired blade profile. A numerical model was carried out and it was found that the Fibonacci shape improves the performance of the original Savonius shape, based on semicircular blade profiles. Particularly, the Fibonacci blade profile increases around 14% the power in comparison with the Savonius blade profile. Besides this comparison between Savonius and Fibonacci, a research study was carried out to improve the efficiency of the Fibonacci turbine. To this end, the effect of several parameters was analyzed: number of blades, aspect ratio, overlap, separation gap, and twist angle. Improvements on the average power greater than 30% were obtained

The Effect of Fluid Flow Current to 30º Blades Achard Turbine Performance

Achard turbine is one kind of vertical axis water turbine that can use to low head water current. Achard turbine can use to river flow or irrigation canal. This is will make an additional function of river and irrigation canal to be a renewable energy resource. The experiment use three blades NACA 0020 Achard turbine in the irrigation canal at Belitang District, West Ogan Komering Ulu. The flow current is 0.55 m/s, 0.61 m/s, and 0.71 m/s. The result shows increasing of CP and CT by increasing of flow current. Maximum CP is 0.1797 at flow current 0.71 m/s. Maximum CT is 0.206 at flow current 0.71 m/s

Neural Network Compensation Control for Output Power Optimization of Wind Energy Conversion System Based on Data-Driven Control

Due to the uncertainty of wind and because wind energy conversion systems (WECSs) have strong nonlinear characteristics, accurate model of the WECS is difficult to be built. To solve this problem, data-driven control technology is selected and data-driven controller for the WECS is designed based on the Markov model. The neural networks are designed to optimize the output of the system based on the data-driven control system model. In order to improve the efficiency of the neural network training, three different learning rules are compared. Analysis results and SCADA data of the wind farm are compared, and it is shown that the method effectively reduces fluctuations of the generator speed, the safety of the wind turbines can be enhanced, the accuracy of the WECS output is improved, and more wind energy is captured