Study on Performance of Variable-pitch Vertical-Axis Wind Turbine with straight blades

Abstract

The paper describes the performance of a micro vertical axis wind turbine (VAWT) with variable-pitch straight blades. A main feature of the variable-pitch angle mechanism is to be able to vary the pitch angles of blades according to the azimuth angle of the main links, without actuators. The performance of the wind turbine was measured by using an open circuit type wind tunnel and a numerical calculation employed the single streamtube model combined dynamic-stall model with different airfoils (NACA0012, 0015, 0018, 0021, 634-221). The performance of self-start and power of the variable-pitch VAWT is larger than that with fixed-pitch blades. We found that VAWT with variable-pitch straight blades has the optimum swing angle and the optimum airfoil.