考虑气动阻尼的浮式风机频域响应分析

Analysis on Frequency Response of Floating Wind Turbine Considering the Influence of Aerodynamic Damping

分析了气动阻尼对浮式风机频域响应的影响.选取美国可再生能源实验室(NREL)提出的5兆瓦(MW)浮式风机模型作为算例,利用气动阻尼计算方法建立气动阻尼矩阵,再基于三维势流理论计算浮式平台的水动力系数,并将系泊系统视为线性弹簧以考虑其刚度,最后在频域内分别建立并求解考虑与不考虑气动阻尼两种情况下的浮式风机刚体运动方程.利用求解频域方程得到的幅频响应算子(response amplitude operators,RAOs)及结合JONSWAP海浪谱得到的响应谱,在频域内分析了气动阻尼对浮式风机刚体运动的影响.结果表明:作业工况下气动阻尼能有效地降低纵荡和纵摇运动RAOs的峰值,且能在一定范围内减小对应自由度上响应谱的幅值和零阶矩.

This study analyzed the influence of aerodynamic damping on frequency domain response of floating wind turbine. The 5 megawatt （MW） floating wind turbine model built by the National Renewable Energy Laboratory （NREL） of America was selected as an example. The aerodynamic damping matrix of the motion for the rigid body was established according to aerodynamic damping calculation method. Hydrodynamic coefficients were computed based on the three-dimensional potential flow theory, and the stiffness of mooring system was also taken into account as linear spring. Motion equations of the wind turbine with or without consideration of aerodynamic damping were then established and solved in frequency domain, respectively. The influence of aerodynamic damping on the motion of the floating wind turbine was examined in frequency domain through the response amplitude operators （RAOs） by solving the equations, and the response spectrum was derived from RAOs and JONSWAP wave spectrum. The results show that aerodynamic damping can effectively reduce the peak values of the surge and pitch RAOs under operating condition, and decrease the amplitude and zero-order moment of the corresponding response spectrum to a certain degree.