Performance Measurement of a Two-Stage Two-Bladed Savonius Rotor

Abstract

Conventional Savonius rotor is the ancient form of Vertical Axis Wind Turbines (VAWT) rotor which has many advantages such as self-starting, omni-directional, less noisy, suitability for applications like pumping, grinding, sailing etc. However, its efficiency is only in the range of 15%-21%. Investigations are being conducted to improve its efficiency by controlling its design parameters. In this paper the performance of a two-stage two-bladed configuration of the Savonius rotor has been investigated. Experiments are conducted in a subsonic wind tunnel available in the department. The parameters studied are overlap, tip speed ratio, power coefficient (Cp) and torque coefficient (Ct). Overlap ratio of the design was optimized to generate maximum performance of the rotor. The study showed that a maximum Cp of 0.517 was obtained at 9.37% overlap condition. Thus Cp of the rotor is much higher than the conventional Savonius rotor

Keywords

• Two-stage Savonius rotor, overlap, tip speed ratio, power coefficient, torque coefficient

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