海上浮式垂直轴风力机系统的刚—柔耦合动力特性及浮式基础非线性运动研究

Comparing with the horizontal axis wind turbines (HAWTs), the vertical axis wind turbines (VAWTs) have the advantages of lower location of the center of gravity, more stable structure, lower installation and maintenance cost. The VAWTs are more economical when the generated power is more than 5MW. The VAWTs will be used to the offshore deep sea wind power in this project, the dynamic characteristic of the large VAWTs supported by the floating foundation and the nonlinear motions of the floating foundation will be studied. Considering the coupling of rigid motions of the floating foundation and the flexible vibration of the wind turbines’ tower, the dynamical models with rigid-flexible coupling motions of the wind turbine system will be established. The phenomena of dynamic stiffening and dynamic softening of rigid motions of the floating foundation to the tower of the wind turbines will be investigated and the natural vibration characteristic of the wind turbine system will be studied more accurately. Considering the rigid-flexible coupling and the influence of the floating foundation motions on the wind force comprehensively, the motion responses of the wind turbine system will be predicted and the critical operation environmental parameters will be ascertained. The yaw of the floating foundation will be analyzed and the ability of resisting torsion of the mooring system will be studied. Considering the wind force and wave force, the nonlinear dynamical behaviors of bifurcation, chaos, energy transfer, ect of the floating foundation will be studied, and the key dynamical parameters that lead to the large amplitude nonlinear motions of the floating foundation will be found. The project will support the theoretical guidances for the parameter design of the offshore floating VAWTs and lay the theoretical foundation for propelling the large-scale development of offshore wind power in our country.

与水平轴风力机相比，垂直轴风力机的重心位置低、结构稳定，安装、维护成本较低，发电功率大于5MW时，垂直轴风力机的经济性能更高。本项目将垂直轴风力机用于海上深水风力发电，研究浮式基础支撑的大型垂直轴风力机系统的刚—柔耦合动力特性及浮式基础的非线性运动。考虑浮式基础刚体运动与风机塔柱柔性振动的耦合，建立风力机系统的刚—柔耦合动力学模型，分析浮式基础运动对塔柱的“动力刚化”和“动力柔化”效应，更合理的研究风力机系统的固有振动特性；综合考虑刚—柔耦合效应及浮式基础运动对风载荷的影响，预报风力机系统的运动响应，确定临界作业环境参数；分析浮式基础艏摇运动，研究系泊系统的抗扭转能力；研究虑风、浪载荷作用下浮式基础的分岔、混沌、能量传递等非线性动力学行为，确定导致浮式基础大幅非线性运动的关键动力学参数。本项目为海上浮式垂直轴风力机系统参数的设计提供理论指导，为推进我国海上风力发电的大型化发展奠定理论基础。

与水平轴风力机相比，垂直轴风力机的重心位置低、结构稳定，安装、维护成本较低，在一定条件下具有更好的经济性能。本项目采用理论分析、数值模拟和模型试验相结合的方法，紧密围绕海上浮式垂直轴风力机系统的刚-柔耦合动力特性及非线性运动展开研究。考虑浮式基础运动，研究了浮式垂直轴风力机系统的气动载荷；提出了风浪载荷作用下浮式垂直轴风力机系统的刚-柔耦合动力学建模方法；研究了风机柔性结构的“动力刚化”和“动力柔化”，分析了风机系统整体和局部固有频率的特点；综合考虑风浪载荷，研究了浮式基础非线性运动特性，确定导致浮式基础大幅非线性运动的关键动力学参数。.本项目开发了浮式垂直轴风力机系统的运动响应计算程序，该程序能够考虑浮式基础与风机结构的刚-柔耦合运动以及气动载荷与水动力的耦合作用；分析了浮式基础运动、塔柱振动、叶片变形间的相互影响；揭示了浮式风机系统的气动载荷由叶片到塔柱到浮式基础的传递过程以及波浪载荷由浮式基础通过塔柱传递到叶片的过程。本项目研究为海上浮式垂直轴风力机系统参数的设计提供了理论指导。