Design and CFD study of a hybrid vertical-axis wind turbine by employing a combined Bach-type and H-Darrieus rotor systems

The objective of this work was to design, simulate and evaluate the performance of an innovative hybrid vertical axis wind turbine (VAWT) for obtaining an extended operational range and enhancing self-starting capabilities. An extensive research was conducted to explore the design parameters for obtaining an optimum novel hybrid VAWT configuration. The hybrid VAWT consisting of a 2-bladed modified Savonius Bach-type rotor and a 3-bladed Darrieus turbine was modeled and analyzed in computational fluid dynamics (CFD) to calculate the characteristic parameters of the rotor system. The geometry was then used to generate the grid in ANSYS Meshing for computational fluid dynamics (CFD) analyses to evaluate the performance of the designed hybrid VAWT. Results indicated that while the Darrieus turbine had the highest coefficient of power (C-p) of 48.4% at a TSR of 2.50, it suffered from high start-up torque requirements. The hybrid turbine demonstrated self-starting capabilities while reaching a maximum C-p of 41.4% at a TSR of 2.5 and operation up to a TSR value of 4.5. When compared to previous hybrid VAWT designs, the proposed configuration demonstrated improvements to the efficiency and operational range which support the energy sustainability prospects.