Numerical and experimental study on a modified Savonius rotor with guide blades

ABSTRACT

Presently Horizontal Axis Wind Turbines are used extensively for generation of electricity from wind. These turbines are not preferred in regions where the wind speed is low and/or wind direction changes continuously. Also, these turbines are not suitable for urban areas where wind turbulence is high and land availability is low. The Savonius wind turbine is a drag-driven Vertical Axis Wind Turbine, which is simple in design and easy to fabricate. Savonius wind turbines have much lower efficiency compared with other lift- driven wind turbines. The present study focuses on increasing the efficiency of Savonius rotor by considering some modifications in the conventional profile of it and placing guide blades around it. Computational Fluid Dynamic (CFD) analysis was conducted for selecting guide blades and predicting the performance of the turbine. An experimental study was conducted with the turbine having proposed modifications, and the results of CFD analysis were validated. The maximum power coefficient obtained from the study is 28%. It was established from the study that guide vanes help to reduce negative torque resulting in increased efficiency. Turbines with proposed modifications can be used even in regions where wind speed is low and turbulence is high.

KEYWORDS:

• Savonius wind turbine
• wind energy
• coefficient of power
• guide blades
• CFD analysis
• moving reference frame

Acknowledgments

The authors express sincere gratitude to TEQIP phase II, a partially world bank funded project for providing financial support for the work.