Performance Analysis of the Savonius-Type Rotor with Grooved Blades as a Hydrokinetic Turbine

The Savonius-type rotor is a phenomenal rotor model applied to vertical-axis type hydrokinetic turbines, which use is quite popular even though its performance is considered lower than other rotor types. One of the advantages of the Savonius-type rotor compared to other types of vertical axis hydrokinetic rotors is that it is more effective in extracting hydrokinetic energy from low velocity water flows. This research aims to analyze the performance of the Savonius rotor by modifying the blade model by providing grooves on the concave side. Tests were carried out on a two-blade Savonius rotor without grooves and with blades using 5, 6, 7 and 8 grooves with a width of 15 mm in the direction perpendicular to the shaft with varying input loads and flow rates for several constant rotation levels. The research results indicate that the groove-less blades yielded a maximum tip speed ratio (TSR) of 1.32 and a maximum efficiency (ɳ) of 29.58%. In contrast, grooved blades produced a maximum TSR of 1.40 and a maximum efficiency of 33.71%, indicating an increase in TSR of 0.08 and an efficiency increase of 4.17 %, with the highest increase occurring on eight-groove blades.