Effect of number of blades on the dynamic behavior of a Darrieus turbine geared transmission system

Abstract

Abstract Dynamic behavior of a Darrieus-type vertical axis wind turbine geared transmission system taking into account variable gear mesh stiffness and the external aerodynamic torque excitation is carried out in the present paper. The aerodynamic torque is obtained by a complete campaign of simulations based on Reynolds Averaged Navier-Stokes unsteady calculations for two, three and four-bladed rotor architectures. A three-dimensional model of a one-stage bevel spur gear system is developed. For each proposed rotor configuration, the effect of the number of blades on both aerodynamic performance and dynamic vibration of the Darrieus turbine geared transmission system is discussed at several tip speed ratios in non-stationary operation. The main originality of the present paper is to establish a correlation between the aerodynamic parts and the dynamic vibration of the gearing system by studying the effect of some design parameters on the dynamic vibration of the Darrieus turbine gearing system in non-stationary regime. This new methodology of simulation makes considerable progress in the understanding of the wind turbine dynamic vibration, which is an important issue. The number of the blades is the core problem of wind turbine engineering. In this paper, the numerical results show that the number of blades significantly affects the turbine efficiency and the dynamic response of the studied wind turbine gearing system in non-stationary regime.