Aerodynamic analysis of a 2-stage elliptical-bladed Savonius wind rotor: Numerical simulation and experimental validation

Abstract

ABSTRACT The Savonius rotor is a type of vertical-axis wind turbine that utilizes drag to generate power. Its design simplicity and ability to self-start at low wind speeds make it an attractive option for small-scale wind energy generation. Previous research has focused on optimizing the geometric configuration of a 1-stage, 2-bladed rotor with semicircular blade profiles to improve its performance and mitigate negative torque. However, limited research has been conducted on 2-stage, 2-bladed Savonius rotors with elliptical blade profiles. The present investigation aims to fill this research gap by evaluating the aerodynamic characteristics of a 2-stage, 2-bladed Savonius rotor with elliptical profiles. 3D unsteady simulations using the SST k-ω turbulence model in ANSYS Fluent are conducted to evaluate the performance coefficients over a range of tip speed ratios. The numerical results are validated through wind tunnel experiments. The results show that the CPmax (maximum power coefficient) for the 1-stage rotor is 0.19 and 0.12 for numerical and experimental analyses, respectively. For the 2-stage rotor, the CPmax is 0.21 and 0.17 for numerical and experimental analyses, respectively. These findings suggest that the 2-stage rotor with elliptical profiles has the potential to efficiently harness wind energy.