考虑叶片停机位置大型风力机塔架风-沙致结构响应分析

Analysis of wind-sand-induced structural response of large wind turbine considering the position of blades

强风停机状态下叶片位置会显著影响风力机塔架的绕流及稳定性能,尤其在沙尘暴极端天气条件下,沙粒的附着也会影响风的湍流特征并对塔架产生附加冲击力,现有工作均缺乏风-沙耦合作用对大型风力机体系气动性能及结构响应的探索。以南京航空航天大学自主研发的5 MW水平轴风力机体系为对象,以风-沙双向耦合算法为核心,基于CFD技术分别采用连续相和离散相模型进行典型风场和沙粒组合的同步迭代模拟。考虑叶片单个旋转周期内8个停机位置,对比分析了风力机塔架表面等效压力系数和气动载荷分布特性;结合有限元方法系统探讨了不同停机位置下风力机体系动力特性、风-沙致结构响应和屈曲稳定性能。研究表明:风-沙耦合环境下沙粒在风力机塔架迎风面底部产生的荷载效应最为显著,部分区域沙致压力系数可达0.55,沙粒冲击荷载与风荷载的比值最高可达23.7%;不同停机位下风荷载均对塔架结构响应起主导作用,但沙粒冲击作用在塔架底部的放大效应不可忽视。

The position of the blades in a strong wind-off state will significantly affect the flow around wind turbine towers and stability of them.Especially in the extreme weather conditions of sandstorms,the adhesion of sand will also affect the turbulence characteristics of the wind and generate additional impact force on the tower.The existing researches lack the exploration of wind-sand coupling effect to explore the aerodynamic performance and structural response of large-scale wind turbines.Taking the 5 MW horizontal-axis wind turbine system independently developed by Nanjing University of Aeronautics and Astronautics as the object and wind-sand-wave two-way coupling algorithm as the core,the simultaneous iterative simulation of the typical wind field and sand combination is performed on the continuous phase and discrete phase model respectively by CFD technology.Considering the eight stop positions in a single rotation cycle of the blade,the equivalent pressure coefficient and the aerodynamic load distribution characteristics are compared and analyzed.Then combined with the finite element method,the dynamic characteristics,wind-sand induced structural response and buckling stability of the wind turbine system at different stopping positions are discussed.The results show that the load effect of sand particles on the windward surface of wind turbine tower is the most significant under the wind-sand coupling environment.The pressure coefficient of sand in some regions can reach 0.55,and the ratio of sand impact load to wind load can reach 23.7%.The wind load under different stand positions plays a dominant role in the response of the tower structure,but the effect of sand impact on the bottom of the tower cannot be ignored.