Vibration Mitigation of Wind Turbine Towers by Tuned Liquid Column Dampers

摘要

Tuned liquid column dampers consist of a U-shaped tank filled with a Newtonian liquid. The tuned parameter of the liquid damper enables the liquid mass to oscillate with a phase shift with respect to the motion of the structure, leading to damping forces on the primary structure. The oscillation energy of the damper liquid dissipates by turbulence effects and friction caused local pressure loss. Due to its geometric flexibility and the low prime costs tuned liquid column dampers are a good alternative to other damping measurements, in particular for slender structures like wind turbines. The effectiveness of the vibration behavior improvement obtained with the TLCD depends not only on the natural frequency and the damping ratio but also on the geometric layout of the damper. This paper presents an expanded optimization approach, which considers the mathematical description of the damper geometry within the tuning procedure. The numerical verification of the novel approach is demonstrated by means of a three-bladed 5 MW reference wind turbine, which is during normal operational conditions periodically and stochastically excited by non-uniform steady state and turbulent wind flow. The acquired results show that TLCD can effectively mitigate wind induced resonant tower vibrations and improve the fatigue life of wind turbines.