Showing papers on "Savonius wind turbine published in 2016"

Experimental Study of Combined Blade Savonius Wind Turbine

Abstract: – Many modifications have been made on c onventional 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 Keywords - Savonius turbine, combined blade, experimental, performance

Development of efficient vertical axis wind turbine clustered farms

Abstract: An efficient triangular shaped three co-rotating Savonius turbine cluster arranged in close proximity shown in Ref. [1] enhances the average output power of its three turbines up to 34% compared to their isolated counterpart. In this study, patterned Savonius vertical axis wind turbine farms are developed for renewable energy generation. The farms consists of multiples of triangular efficient three turbine clusters. The three turbine cluster has a triangular shape and the turbines inside the cluster are arranged in a close proximity to enhance their average output power. The efficient Savonius wind turbine farms are developed using the enhanced three co-rotating triangular turbine cluster of Ref. [1] as the building unit. The developed farms consist of multiple clusters with scaled geometrical ratios of the three turbine cluster keeping the same topology of the cluster. This resulted in patterned farms that have the same power enhancement ratio of the three turbine cluster. Numerical simulations of farms that consist of nine and twenty-seven turbines confirm the enhancement and the pattern progression for larger farms. Numerical results are obtained using Fluent code.

Geometrical optimization of a swirling Savonius wind turbine using an open jet wind tunnel

Abstract: It has been suggested that waste heats or naturally available heat sources can be utilized to produce swirling flow by a design similar to that of split channels which is currently used to initiate fire whirls in laboratories. The new design combines the conventional Savonius wind turbine and split channel mechanisms. Previous computational and preliminary experimental works indicate a performance improvement in the new design (named as swirling Savonius turbine) compared to the conventional Savonius design. In this study, wind tunnel experiments have been carried out to optimize the swirling Savonius turbine geometry in terms of maximum power coefficient by considering several design parameters. The results indicate that the blade overlap ratio, hot air inlet diameter and the condition of the top end plate have significant influence on power and torque coefficients, while a larger aspect ratio and closed top end plate have some favourable effects on the performance. The optimum configuration has been tested in four different wind velocities to determine its influence on the performance, and power coefficients were found to be higher in high wind velocities. The performance comparison of optimum configuration with conventional Savonius rotor showed an increase of 24.12% in the coefficient of power.

Numerical investigation of Savonius wind turbine farms

Abstract: The Savonius vertical axis wind turbine is a simple device, easy to manufacture, has good starting characteristics, and rotates with wind from any direction; nevertheless, it has a lower efficiency than the other wind turbines. The aim of this paper is to numerically explore the non-linear unsteady flow over a conventional Savonius using three dimensional computations with emphasis on the placement of these turbines in a linear array and the effect of an obstacle that acts as a wind deflector. First, an infinite array of turbines is used to study the gap distance between the wind turbine axis rotors. This investigation is conducted via numerical simulations based on the computational fluid dynamics computer program Fluent 14.5. It is found that a gap distance L = 1.4R gives a very good performance. Second, four farms with different number of turbines—from 3 to 21 turbines—are studied. The effect on the power coefficient of the number of turbines in each farm is reported and analyzed. Third, a new arrangement that includes an obstacle at one end of the array of turbines is presented. The best configuration explored in this work increases the power coefficient of each Savonius wind turbine by 82% compared to a single turbine. Finally, the effect of the wind direction for the best configuration is presented and the range of wind angles for which the farm outperforms isolated turbines is calculated.

CFD Analysis of a Finite Linear Array of Savonius Wind Turbines

Abstract: Vertical axis wind turbines such as Savonius rotors have been shown to be suitable for low wind speeds normally associated with wind resources in all corners of the world. However, the efficiency of the rotor is low. This paper presents results of Computational Fluid Dynamics (CFD) simulations for an array of Savonius rotors that show a significant increase in efficiency. It looks at identifying the effect on the energy yield of a number of turbines placed in a linear array. Results from this investigation suggest that an increase in the energy yield could be achieved which can reach almost two times than the conventional Savonius wind turbine in the case of an array of 11turbines with a distance of 1.4R in between them. The effect of different TSR values and different wind inlet speeds on the farm has been studied for both a synchronous and asynchronous wind farm.

Numerical simulation of a Savonius turbine above an infinite-width forward facing step

Abstract: The Savonius turbine, although simple in construction, typically has a maximum power coefficient (cP) of about 0.2. This is significantly lower than the cP of the axial flow propeller-type turbine which typically can be as high as 0.5. However, a simple means to improve the cP of a Savonius turbine is to install it above a forward facing step, for example, a cliff or a building. In this work, prior experimental results of the tow testing of a Savonius turbine installed above a finite-width bluff body were used to validate computational fluid dynamics simulation of the same experimental conditions. The validated simulation settings were then used to obtain the maximum cP of a similar turbine of finite width but installed above an infinite-width forward facing step over a range of installation positions above and behind the step.

Simulation analysis based performance comparison for vertical axis wind turbines

Abstract: Traditional Savonius wind turbine has advantages such as simple structure, fast start-up, etc., however, it also has significant disadvantages of low wind energy utilization efficiency. A novel wind turbine is proposed by improving structure of Savonius wind turbine in order to increase the low wind energy utilization efficiency. To compare performance of the novel wind turbine and the Savonius wind turbines with two and three blades, two working conditions are investigated. The first is that the wind turbines work in a certain wind speed level to investigate influence of the changing load. The other is that the wind turbines work in a certain tip speed ratio level to investigate influence of environment such as wind speed changing. Considering costs of prototypes, the Computational Fluid Dynamics transient simulation method is used to achieve the analysis. The simulation results show that the novel wind turbine has high load capacities at different situation. The novel wind turbine has higher wind energy utilization efficiency and has good operating characteristics in low wind speed range than traditional Savonius wind turbines.

Modification and Testing of Wind Turbine with Double Savonius

Abstract: Indonesia geographically located at tropical region where the wind is very fluctuate and relatively slow. Therefore it is important for designer to investigate the proper design of the slow wind speed turbine that applicable in Indonesia. In this paper, Savonius wind turbine is selected and modified with double level to explore its capability in generating voltage. The main aim of this study is to investigate the performance of the double Savonius turbine in term of its capability in generating voltage. In experimental test, it can be obtained that the double Savonius Turbine could effectively generate 12V at 3 m/s and 17V at 5.4 m/s.

Simulation Savonius Wind Turbine with Multi-Deflector

Abstract: This paper aims to study the windmill Savonius with multi-deflector. Multi-deflector placed around the windmill, which aims to reduced negative torque to the returning blade and directing the flow of wind to the advancing blade . CFD analysis with ANSYS software. The initial conditions with variation wind speeds 3, 4, 5 and 6 m / s. The result indicated by velocity distribution at positions 00, 450, 900 and 1350. The largest static torque occurs at position 450 caused by the greater the Coand-like flow, dragging flow and overlap flow. The greater the static torque that occurs with increasing wind speeds.

Numerical Investigation and Improvement of Aerodynamic Performance of Savonius Wind Turbine

Abstract: 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.

Influence of the side-by-side arrangement on the performance of a small Savonius wind turbine

Abstract: Scaled-down Savonius turbine rotors arrayed side-by-side are introduced to analyze the effects of design parameters on the performance between turbine rotors. Unsteady flow simulation and experimental measurement have been performed to compare turbine performance and validate the numerical simulation of the turbine rotor. Commercial code, SC/Tetra, which uses an unstructured grid system, has been used to solve the three-dimensional unsteady Reynolds-averaged Navier–Stokes equations. Single turbine rotors and two turbine rotors arrayed side-by-side were numerically analyzed. The distance between rotor tips is 0.5 times the rotor diameter. Throughout the numerical simulation, the power coefficient obtained by the time-averaged result of unsteady flow simulation was found to be in good agreement with the experimental result. A discussion on the design parameters using both a single and arrayed turbine rotors is presented based on the results of the unsteady flow simulation, including the flow field, power coefficient, velocity and vorticity contours.