Reliability Analysis of Aerodynamic Performance and Fatigue Life for Vertical Axis Wind Turbine Rotors

Abstract

Aiming at the unclear coupling mechanism between aerodynamic load and structural fatigue response of vertical axis wind turbine (VAWT) rotors under spatiotemporal uncertain wind loads and the lack of a full‐process analysis method system, this paper takes a four‐blade VAWT rotor with NACA0018 airfoil as the research object. The fluid‐structure interaction (FSI) numerical simulation method is adopted, combined with S‐N curve, Miner linear cumulative damage theory and nCode DesignLife fatigue analysis tool, to systematically explore the aerodynamic characteristics of the rotor under different wind speeds, calculate its fatigue life, and complete structural optimization. The results show that the optimal tip‐speed ratios (TSRs) of the rotor at wind speeds of 4, 8, and 18 m/s are moderate values, 1.78 and 1.58 respectively. The lift‐drag characteristics of the blade are dominated by the angle of attack and are less affected by wind speed. The fatigue weak areas of the rotor are the joints between the blade and the support rod, and between the support rod and the rotating shaft, where the equivalent stress increases sharply at high wind speeds. After optimization by local thickening of the blade, adding reinforcement rings to the support rod and hollowing the main shaft, the maximum equivalent stress of the rotor is greatly reduced. The optimized rotor life reaches 33 years based on the maximum wind speed probability distribution of Bairin Left Banner, and 18.55 years under extreme wind speed, meeting the 20‐year design service requirement. The research results can provide theoretical basis and technical reference for the aerodynamic optimization and fatigue reliability design of VAWT rotors.