湍流风对铰接式海上风力机动力响应的影响

为适应中等水深风电开发的需要,进一步降低成本,在铰接塔平台的设计基础上,设计了一种铰接式海上风力机,研究了其在工作海况和极限海况下湍流风对风力机动力响应的影响.采用叶素动量理论计算气动载荷,势流理论计算波浪载荷,考虑风浪流的联合作用,以及瞬时湿表面变化及铰接接头的摩擦阻尼,编写了风浪流时域耦合动力响应分析程序.使用NPD谱模拟湍流风,从而计算得到了定常风和湍流风作用下铰接式海上风力机的动力响应,分析了湍流风对于风力机运动响应和发电效率的影响. 结果表明,湍流风作用下,风轮加速度和铰接点的垂向拉力变化较小,摆角、风轮推力、发电功率和铰接点水平推力的均值分别减小,但摆角和发电功率的响应变化幅度增加.另外,湍流风本身的低频特性会增大系统的低频响应,使系统产生共振.极限海况下,铰接式基础最大摆角显著增大,但依然满足生存需求.因此,湍流风对铰接式风力机的动力响应影响较大,铰接式海上风力机运动和强度分析时不可忽略湍流风的影响.

Influence of turbulent wind on dynamic response of articulated wind turbine

To meet the needs of offshore wind power development in medium depth water and reduce the cost, an articulated wind turbine was designed based on articulated platform. The influence of turbulent wind on the dynamic response of the articulated wind turbine in working and extreme sea conditions was studied. The blade element momentum theory was utilized to calculate the aerodynamic load and the potential theory was applied for the simulation of wave load. Considering the coupled loads of wind, wave, and current, the instantaneous change in wet surface as well as the friction damping of the articulated joint, a calculation software was written and time domain dynamic response of the wind turbine was calculated. Based on the NPD spectrum of turbulent wind, the dynamic response of the articulated wind turbine under the loads of constant wind and turbulent wind were calculated, and the influence of turbulent wind on the dynamic response and energy efficiency of the wind turbine was analyzed. Results show that with turbulent wind, the wind wheel acceleration and the vertical pull force on the articulated joint had little change. The mean values of oscillation angle, stream-wise thrust, output power, and stream-wise thrust force on the articulated joint decreased, but the amplitudes of oscillation angle and output power increased. In addition, the low-frequency characteristics of turbulent wind could increase the low-frequency response of the system and thereby cause system resonation. In extreme climate condition, the maximum stream-wise oscillation angle of the articulated foundation increased significantly, but the turbine system still met survival requirements. Hence, turbulent wind has great influence on the dynamic response of articulated wind turbine, and it is necessarily to consider the impact of turbulent wind when analyzing the movement and strength of articulated wind turbines.