Fusion of spatio-temporal domains for reliability study of vertical axis wind turbine units

The vertical axis wind turbine (VAWT) impeller, a key component in advancing the wind energy sector, demonstrates high levels of performance and operational reliability. Its fatigue failure primarily results from prolonged exposure to low-amplitude cyclic loading rather than from extreme load events. This study incorporates a spatio-temporal wind speed model, using representative wind speed data from Abaga Banner and Pudong District as cyclic load inputs. Through fluid-structure interaction (FSI) numerical simulations, the aerodynamic loading characteristics and structural reliability of the VAWT impeller are comprehensively analyzed. A three-dimensional model of the impeller is developed using LY12CZ aluminum alloy, with detailed mesh refinement and boundary condition settings applied to verify the convergence and mesh independence of the internal and external flow domain models. The pressure distribution and lift-drag characteristics across the blade surface at the optimal tip speed ratio are examined. The results indicate that the highest equivalent stress concentration, reaching 4.719×10⁷ Pa, occurs at the blade-to-support rod connection. Fatigue life analysis based on the p-S-N curve demonstrates a significant improvement in impeller reliability under extreme wind speed conditions (U₀ = 15.8 m/s) following structural optimization. The addition of stiffeners enables the impeller to satisfy 99.9% high-reliability operational requirements. This study provides a theoretical foundation for design optimization and service life evaluation of VAWT impellers.