风-浪-流-RNA运行耦合作用下近海风电结构动态响应分析

Dynamic response analysis of offshore wind turbine under the coupling effects of wind,wave,current and RNA operation

近海风电结构不仅长期遭受风、浪、流等荷载的耦合作用,还需承担风轮-机舱组件(Rotor-Nacelle Assembly,RNA)运行作用带来的额外动力影响,这不仅会加剧结构受载集中部位的损伤,还会影响甚至中断发电机组的正常运作。为探索近海风电结构关键部位的动力特性及振动模式,该文建立考虑风-浪-流-RNA运行的单桩风电塔的耦合分析模型,采用Von Karman风谱模型和叶素动量理论计算气动荷载,通过莫里森方程求取单桩基础结构的波浪及海流荷载,对NREL 5MW单桩塔的塔顶、叶根及单桩底部开展动力响应分析。基于频谱分析法探究结构各关键部位的响应激励源;研究了在3~30m/s风速范围内,近海风电结构动态响应随风速及海流流速的动力特性变化规律。结果表明:近海风电结构动态响应在不同工作状态下会呈现不同的频谱特征,其动态响应时程的均值与峰值随风速增加呈非线性的变化趋势。

Offshore wind turbines not only suffer from the coupling effects of wind,wave,current and other loads for a long time,but also need to bear the additional dynamic impact induced by the operation of Rotor-Nacelle Assembly(RNA),which may not only aggravate the damage of the load concentrated part of the structure,but also affect or even interrupt the normal operation of the generator set.In order to explore the dynamic characteristics and vibration modes of key parts of offshore wind turbines,a coupling analysis model of monopile wind turbine considering wind wave current RNA operation is established.The aerodynamic load is calculated by von Karman wind spectrum model and blade element momentum method.The wave and current load of monopile foundation structure are calculated by Morrison equation,and then the dynamic response analyses of tower top,blade root and single pile bottom are carried out.Based on the spectrum analysis method,the response excitation sources of key parts of the structure are explored.The variation of dynamic response of offshore wind turbine with wind speed and current velocity in the wind speed range of 3~30 m/s is studied.The results show that the dynamic responses of offshore wind turbines exhibit different spectral characteristics under different working conditions,and the mean and peak of the dynamic response time history may change nonlinearly with the increase of wind speed.