With the increasing demand for clean, renewable energy sources, vertical-axis wind turbine (VAWT) research has gained considerable interest. The technology is primarily used for small-scale power applications in environments with unsteady wind conditions, such as urban locations. For this type of turbine the most important features are self-starting characteristics and energy conversion efficiency. For the Savonius type rotor, performance is increased by reducing drag losses on the advancing blades. The present study addresses the numerical verification of the performance of new designs for drag-driven VAWTs.
Two new models were created using SolidWorks along with a standard Savonius model consisting of semicircular blades for benchmarking. All models were designed with the same swept area for comparison. 3D numerical simulation was completed using ANSYS FLUENT. Static conditions were first solved with a moving reference frame (MRF). The results from the MRF simulations were then used to initialize the transient solvers using sliding mesh models (SMM). 3D pressure distributions on the moving blades for each model were analyzed. From inputs of wind and rotational speed, torque values and coefficients of moment were reported. Each model was tested over a range of tip-speed ratios, and power coefficients were calculated. Results were compared to a standard Savonius VAWT, and increased maximum power coefficient was achieved with the new blade geometries.