Study of adaptive blades in extreme environment using fluid-structure interaction method

The extreme environment caused by the typhoon has destroyed several wind turbines in recent decades and already become a restriction to the further development of offshore wind turbines of China. Due to the destructive energy in the typhoon, the conventional active control method for load mitigations of the blades such as the yaw and pitch systems are difficult to implement effectively. Therefore, the adaptive blade that can mitigate the extreme load passively may be a more promising method. In this paper, the adaptive bend-twist coupling blades were investigated on their load mitigation effects. According to a parameterized modeling process, the high fidelity CFD and FEM models for different kinds of bend-twist coupling blades are established. Then the FSI simulations are used to study the mitigating effects of these blades when the blade suffers the extremely dangerous conditions in typhoon environment. The results demonstrate that the swept blade combined with the material coupling can effectively reduce the aerodynamic load and the maximum stress due to the special pattern of the blade deformation. For the case which is easy to cause a high frequent vortex vibration, the swept blades also show a good performance to decrease the dominant frequency and amplitude of the load fluctuation, which is helpful to avoid damages caused by the resonance vibration. (C) 2019 Elsevier Ltd. All rights reserved.