Aerodynamic characteristics optimization of H-type vertical-axis wind turbine based on genetic algorithm

Traditional wind turbines can be classified into horizontal-axis wind turbines (HAWT) and vertical-axis wind turbines (VAWT) based on the geometric relationship between their rotor axis and the horizontal plane. VAWTs do not require automatic yawing systems and have a low center of gravity, good stability, and lower manufacturing and maintenance costs compared with HAWTs. However, it is a consensus in the wind power industry that the single-machine power generation efficiency of VAWTs is lower than that of HAWTs. Therefore, by optimizing the aerodynamic characteristics of individual VAWT, the efficiency of single machines can be improved, thereby achieving efficient operation of VAWTs in grid-connected arrays. In this paper, the National Advisory Committee for Aeronautics (NACA) model NACA0012 airfoil was selected for the overall design of a 10 MW H-type three-blade VAWT. Combined with the optimal Latin hypercube sampling method, the class/shape transformation method was used to mathematically express and deform the NACA0012 airfoil. Based on STAR-CCM+, computational fluid dynamics methods were used to numerically simulate a series of samples. For two important parameters characterizing aerodynamic characteristics, horizontal thrust coefficient, and energy conversion efficiency, a multi-objective optimization problem was established. Multi-objective genetic algorithm was used to optimize them to obtain the Pareto solution set. Typical optimization results from the solution set were selected for analysis. The optimization results show that when the inlet wind speed is 10 m/s and the blade tip velocity ratio is 4.5, compared with the NACA0012 prototype, the optimization result in this paper is at the cost of increasing the horizontal thrust coefficient by 5.45%; meanwhile, the actual operating power of wind turbine is increased by 1.489 MW and the energy conversion efficiency is increased by 13.78%. Additionally, the reduction in the cross-sectional area of a single blade contributed to improved economic efficiency. This paper is dedicated to the research on the optimization of fixed VAWT airfoils and provides examples of aerodynamic performance optimization. It also lays a certain research foundation for subsequent optimization research on floating VAWTs under deep-sea conditions with wind-wave flow coupling.