大尺寸风力机叶片流固耦合特性研究

摘要

With the increasing of large-scaled wind turbines blade size,its flexibility is also growing up.It will be more prone to lead to larger structural deformation phenomena in the operation,nonlinear aeroelastic response,and different power performance and instability problems.To predict the nonlinear aeroelastic responses of large wind turbine,it makes sense to develop a new fluid-structure interaction model.A new fluid-structure interaction model including a nonlinear beam based on the geometrically exactly beam theory and an unsteady aerodynamic model based on vortex flow wake theory is applied to study Fluid-Structure Interaction characteristics of large size blade.For the effects of the flexible blade,weight-reduction techniques and increased size.Respectively,using the method that reduce the blade stiffness and reduce the quality.The effects of the large deformation and light weight on the coupling response were studied.The results show that the reduction of the stiffness will greatly increase the deformation and load of the blade,but the effect of the quality reduction on the blade deformation and load is not obvious.When the stiffness and quality are reduced at the same time,the deformation of the blade which is outside of the impeller plane will substantial increase,resulting in impeller power decrease.The influence of the size of rotor is also studied.And the results show the increased root stress and larger fluctuate of coupled response.%随着大型风力机叶片尺寸增大,其柔性也越来越大,在运行中更容易出现大变形现象,进而导致叶片结构的几何非线性变形、流体的非定常特性以及独特的流固耦合现象,需要采用更准确的模型进行分析.该文采用基于几何精确梁方法和自由涡尾迹方法的流固耦合模型,研究了大尺寸叶片的耦合特性.针对叶片柔性变大、质量变轻的特点,分别采用缩小叶片刚度和质量的方法,研究叶片大变形和质量变轻对耦合响应的影响,结果表明刚度降低会大幅增大叶片变形和载荷,而质量降低对叶片变形和载荷的影响并不明显.当刚度和质量同时降低时,叶片在叶轮平面外变形量大幅增加,使叶轮功率下降.对叶片尺寸变大带来的影响也进行了研究,发现大尺寸叶片的根部应力和载荷波动会较明显高于小尺寸叶片.