Numerical investigation on torque performance of darrieus-savonius hybrid designs

Abstract

Studies are ongoing on hybrid turbine designs that combine the strengths of Savonius and Darrieus turbines to eliminate their weaknesses and perform efficiently in areas with low and fluctuating wind speeds. This study was conducted to contribute to the development of various hybrid designs and analysis methods in the literature. In this study, two different Darrieus-Darrieus and two different Darrieus-Savonius hybrid turbine designs are proposed with the expectation of achieving better torque and power efficiency. Two-dimensional unsteady RANS CFD analyses have been performed on these turbines. The changes in torque values over time are presented graphically, and the flow characteristics, turbulence intensity, and wake flow have been analyzed. As a result, it has been determined that hybrid designs, while not producing as much power as the standard Darrieus turbine, provide higher torque at low TSR with the nested Darrieus design. The Darrieus-Savonius hybrid produces better torque than the double Darrieus design at low TSR but its performance decreases at high TSR. This study shows that the presented hybrid turbines provide advantages at low TSR but need improvements in terms of power production.

Keywords

• Wind energy
• Darrieus
• Savonius
• Hybrid VAWT
• Torque
• Tip speed ratio
• Unsteady CFD.

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