Study on vibration characteristics of wind turbines under different wind speeds

Abstract

When the wind turbine blades are running under normal conditions, the blades will vibrate due to periodic aerodynamic forces, and the use time of blades will be reduced. In order to study the vibration characteristics of wind turbine blades, this paper selects 5 operating conditions (wind speed range from 15 m/s to 40 m/s) under different wind speed conditions. The CFD method is used to simulate the NREL PHASE VI blade, and the vibration and vibration displacement curves under different wind speeds are obtained. The results show that: 1) the main vibration modes of the blade are waving and shimmy, and the high order blade vibration modes have complex deformation of bending and torsion. 2) When the inlet velocity increases from 15 m/s to 40 m/s, the uneven distribution of pressure distribution on suction surface is increasing, and the maximum pressure difference is about 3 000 Pa when the inlet velocity is 40 m/s. 3) when the flow velocity is 15 m/s, the minimum amplitude is 0.525 4 mm, and when the flow velocity is 40 m/s, the vibration reaches the maximum of 3.628 2 mm, which is about 6.9 times of the minimum amplitude. The vibration curves of the 5 operating conditions are all attenuated trend and the blades tend to stabilize vibration, and when the wind speed is larger, the aerodynamic force generated by the wind flow has a greater force on the blade, and the amplitude of the blade tends to increase. The results of this study can provide a reference for the design of wind turbines.

Keywords

• nonlinear vibration mechanics
• nonlinear vibration system
• wind turbine
• blade
• computational fluid mechanics(CFD)