来流条件对风力机叶片流固耦合特性影响研究

The Effect of Wind Shear on Wind Turbine Blades Fluid-structure Coupling Characteristics

针对不同来流条件引起的风力机叶片振动问题,通过数值方法研究流速以及风剪切指数对叶片流固耦合振动的影响规律。以NREL 5MW风力机叶片实尺度模型为研究对象,采用不同风剪切指数的来流入口条件,利用数值方法获取不同来流工况下叶片表面载荷、压力分布以及载荷随方位角的变化规律;基于单向流固耦合方法计算不同工况下结构耦合形变、应力、应变以及模态频率。结果表明:叶片主要承受轴向载荷作用,叶片表面载荷最值主要在叶展方向85%至90%截面段;与均匀流作用下的耦合结果对比,风剪切来流作用下叶片截面载荷、压力分布以及结构耦合变形、应力、应变以及模态频率均增大,且随风剪切指数的增大而增大;因此,在开展风力机叶片流固耦合研究时,考虑风剪切的影响能够更准确地反映大气边界层中流体对叶片的耦合作用,对风力机叶片流固耦合动力特性的研究有很大意义。

In order to solve the problem of wind turbine blades vibration caused by different inflow condition, the influence of flow velocity and wind shear index on fluid-solid interaction(FSI) of wind turbine blades are studied by numerically simulation. Based on the NREL 5 MW wind turbine blades, the entry conditions of different wind shear indices were used to obtain the blade surface load, pressure distribution and the variation of load with azimuth under different inlet conditions by FSI numerical method. For each of the inflow cases, the coupled deformation, stress, strain and modal frequency of the structure under different working conditions are calculated by means of unidirectional FSI method. The results show that: The blades are mainly bear axial load, and the max fluid load of blades is mainly concentrated at the section of 85% to 90% of blades in the direction from blade root to top. Compared with the uniform flow cases, all of the fluid load, pressure distribution, coupled deformation, stress, strain and modal frequency of the blade increase under the action of wind shear inflow. And also increases with the increase of wind shear index. Therefore, when analyzing the FSI problem of wind turbine blades, considering the influence of wind shear can more accurately reflect the coupling effect of the fluid in the atmospheric boundary layer on the blades, which is of great significance to study the FSI dynamic characteristics of wind turbine blades.