Experimental Investigation of Zigzag Height Variation on the Concave Blade Surface and Its Impact on Savonius Rotor Performance

Clean energy offers a sustainable alternative to decreasing reliance on fossil fuel sources that significantly contribute to global CO2 emission and climate change. Wind energy extracted commonly using wind turbines has emerged as a viable and eco-friendly choice among many renewable energy sources. A Savonius rotor as a vertical axis wind turbine is especially suitable for small-scale energy generation units due to its straightforward design, economic viability, and efficiency in low wind speed areas. This report examines the impact of altering the zigzag pattern heights on the central area of the concave blade surface on turbine performance. The investigation was experimentally conducted to test the variation of such blade designs on turbine efficiency. The turbine performance parameters, including power and torque coefficients, were assessed. A conventional Savonius turbine using semi-circular blades was employed to undertake additional testing for comparison. The turbine achieved the highest power coefficient of 0.315 at a tip speed ratio of 0.8 at a wind speed of 6 m/s for turbine blades using a 2 mm zigzag pattern height. This model performed a wide range of efficiency with tip speed ratio values ranging from 0.6 to 0.8. In comparison to the conventional Savonius blades, a 26.5% increase in efficiency was observed. Consequently, this investigation has shown that the power coefficient could be substantially improved by implementing a 2 mm zigzag modification on Savonius turbine blades.