The aerodynamic performance of H-type darrieus VAWT rotor with and without winglets: CFD simulations

In this study, the H-Rotor vertical axis wind turbines with and without winglets are simulated by ANSYS CFX software based on structured meshing technology and incompressible continuity Reynolds Averaged Navier-Stokes equations (RANS) solver. It is shown that the CFD and experimental results of the rotor power coefficient have a good agreement during the range of calculations. The rotor power coefficient of H-type vertical axis wind turbine with winglets is 10% to 19% higher than that of the original H-type vertical axis wind turbine. In each revolution, the output torque of H-type vertical axis wind turbine with winglets is larger than that of the original H-type vertical axis wind turbine at every azimuth angle; the maximum torque increases by 12.8% and the negative torque is avoided when tip ratio reaches 1.53; the minimum and maximum thrust increase by 26.7% and 3.4%. The vorticity distribution at the tips of wingletted H-Rotor blades are weaker than the H-Rotor without winglets. The aerodynamic performance of the near region of blade tips is improved. Winglets increase the overall torque-generating, but does not improve it at every azimuth angle for each blade. The reported results may provide a valuable reference or benchmark for the design and optimization of future wingletted H-Rotor VAWTs.