二阶波浪力下6 MW单柱浮式风力机动态响应分析

Dynamic response analysis of a 6 MW spar-type floating offshore wind turbine under second-order wave forces

摘要:

为了实现在中等深度海域浮式风力发电机的规模应用, 解决能源短缺问题, 针对设计出的新型6 MW海上单柱浮式风力机的生存能力进行探讨, 利用Sesam软件获取二阶波浪力计算时所需的wamit文件, 利用气-液-固-弹性数值软件FAST对该浮式风力发电机进行时域耦合运动响应仿真模拟.分别就不同浪向下平台各自由度的运动响应、二阶平均波浪力和二阶慢漂波浪力对平台各自由度运动响应的影响、二阶平均波浪力和二阶慢漂波浪力对锚链张力和机舱的影响进行了研究.结果表明:首摇运动随浪向角增大而增大, 而波浪入射角对其他各自由度运动影响较小; 二阶慢漂力对垂荡运动影响显著, 且易激发较大的纵摇运动响应, 并诱发较大的锚链张力; 采用delta-line的系泊系统能够避免产生过大的首摇响应, 且系泊系统的最大张力远在破断张力以下, 整个风力机系统在恶劣海况下具有良好的生存能力.

Abstract:

To realize the scale application of floating wind turbines in medium depth sea areas and solve the problem of energy shortages, viability of the new 6 MW spar-type floating offshore wind turbine (FOWT) was discussed by using Sesam software and aero-hydro-servo-elastic simulation code-FAST software.The wamit files of second-order wave force were calculated by the former and the dynamic response coupling analysis in time domain was carried out by the latter.The motion response of each DOF under different incident angles of wave and the effect of the second-order mean wave force and the second-order slow wave drift force on the motion response of the platform, mooring tension force and nacelle acceleration were researched respectively.The results showed that the yaw motion of the platform became more obvious when the incident angle of wave increased, while the other DOFs motion were affected little.The second-order slow drift wave force had a significant effect on the heave motion, and could stimulate a larger pitch motion response and induce larger mooring force.Moreover, the delta-line mooring system could avoid excessive yaw response and the maximum mooring force was below the breaking tension.Finally, the whole FOWT system had an excellent survivability in the harsh sea conditions.