台风过境下大型单桩式海上风机结构动力特性研究

风机大型化是我国海上风电技术发展的重要方向. 东南沿海是我国海上风电发展的重要基地, 这一区域频繁发生的台风对海上风机的影响不可忽略. 台风风场与常规大风风场有不同的湍流特性, 同时台风期间较高的风速会引起巨大的台风浪. 本文考虑台风经过期间独特的风场及波浪场, 开展风浪联合作用对大型单桩海上风机影响的研究. 基于DTU 10 MW大型单桩风机, 运用一体化分析软件SIMA建立风浪联合作用下大型单桩风机的耦合数值模型, 研究台风经过不同阶段大型风力机的动力响应特性. 计算结果显示, 叶片变桨能有效降低台风经过时风机叶片所受风载荷, 变桨状态下单桩风机所受风载荷主要来源于塔筒. 在台风经过的不同阶段, 大型单桩海上风机结构表现出不同的动力特性. 台风全过程塔筒运动均受波浪激发一阶频率控制, 塔基上方结构动力载荷以惯性载荷为主, FOVS至FEWS阶段及BOVS阶段至BEWS阶段塔筒运动一阶频率处响应能量增长较小, 响应能量向低频及波频转移. 塔基下方泥面线处剪力响应受波频控制, 弯矩响应受一阶频率控制. 

RESEARCH ON DYNAMIC CHARACTERISTICS OF LARGE-SCALE MONOPILE OFFSHORE WIND TURBINE UNDER TYPHOON EVENT1)

Large scale wind turbine is an important direction of offshore wind technology in China. The southeast coast is a vital base for the development of offshore wind. However, the impact of typhoon events, which frequently occurs in this area, can not be neglected. The turbulent properties of typhoon are different from the normal strong wind. Meanwhile, the high wind speed during the typhoon events can lead to large typhoon waves. The aim of present work is to study the dynamic characteristics of the large scale monopile offshore wind turbine (OWT) during different typhoon stages, considering the unique wind and wave fields caused by typhoon. The DTU 10 MW monopile-type OWT were investigated using an integrated software, Simulation Workbench for Marine Application (SIMA) and the numerical model is established. The results show that pitch control can effectively reduce the wind loads on the blade during the typhoon event, and the wind loads on the turbine supported by monopile foundation mainly comes from the tower. At the different stages of the typhoon, the large-scale monopile offshore wind turbine exhibits different dynamic characteristics. The tower movement during the entire typhoon process is controlled by the first-order nature frequency which was excited by waves. The dynamic load of the structure above the tower base is dominated by inertial loads. The response energy growth rate at the first-order frequency of the tower movement is decreasing as the wind speed is increasing. And the response energy transfer to low frequency and wave frequency. The dynamic load under the base is obviously affected by wave load and wind load, shear response is controlled by wave frequency while bending moment response is controlled by first order eigen frequency and it is also greatly affected by the wave frequency and low frequency induced by wind at the mudline below tower base.