Review of Specific Performance Parameters of Vertical Wind Turbine Rotors Based on the SAVONIUS Type

Increasing energy demand and environmental regulations around the world provide an adequate framework for developing methods of obtaining energy from renewable sources. Wind force is a resource with a high potential through which green energy can be obtained with no negative impact on the environment. Different turbine typologies have been developed, which can convert the wind force into mechanical and electrical energy through turbine rotational motion. Starting from the classic vertical-axis SAVONIUS rotor model, other models have been designed, which, according to the numerical studies and experimental test results, show higher performance parameters in operation. Such models present specific rotor blade geometries to achieve better operational results in terms of shaft torque and generated power. There are multiple research results from numerical analysis on virtual models or experimental tests that use rotor models in different constructive configurations aiming to improve operation performance. These research activities are related to the rotor blade number, the aspect and overlap ratio values, the blade profile geometry modification, the use of end plates connected to the rotor blades, curtain mounting solutions for directing the air flow on the active blade alone, and rotor constructive variants with deformable blades during operation. Some of the results obtained from the mentioned research activities are shown in this review for special rotor configurations whose performance results in terms of torque or power values are compared to the classical SAVONIUS model.