A novel hybrid approach for high-efficiency and low-load airfoil design for H-type vertical axis wind turbines

The bionic approach enables the rapid excellent design, avoiding the complexity and time-consuming traditional optimization processes. To swiftly develop a high-efficiency airfoil suitable for vertical axis wind turbines (VAWTs), this study designs a novel dolphin-average airfoil (Dol-Ave airfoil) inspired by the streamlined profile of the Dall's porpoise's head. Furthermore, considering the challenges in aligning biologically inspired designs with practical engineering requirements, the Archive-based Micro Genetic Algorithm (AMGA) is adopted to refine the Dol-Ave airfoil contours by targeting high energy capture efficiency and low load. The combination of bio-inspired method and numerical optimization is referred to as the hybrid optimization method. The results of numerical simulations and comparative verification show the following: (1) When tip-speed ratio(TSR) is 0.5, compared to National Advisory Committee for Aeronautics (NACA) 0018 airfoil, the power coefficient of the Dol-Ave airfoil increases by 52.66%. However, under the high tip-speed ratio conditions, no improvement in wind energy utilization is observed. (2) The optimized airfoil (Dol-Ave opt) achieves power coefficient optimization across the full tip-speed ratio range. Compared to NACA 0018, when TSR = 0.5, the power coefficient of the Dol-Ave opt airfoil increases by 30.01%; when TSR = 1.2, the increase is 8.16%. (3) Both the Dol-Ave airfoil and the Dol-Ave opt airfoil show improvements in lateral thrust load. The bio-inspired airfoil design method and the hybrid design approach proposed in this study offer valuable insights for airfoil design.