恶劣环境下大型风力机叶片稳定性问题研究

发布时间：2018-08-12 16:26

【摘要】：风力机叶片是风力发电机的重要组成部分之一。随着风力机的大型化，叶片尺度不断增大，大型风力机在阵风和暴风环境下运行时，会出现结构振动、变形等不稳定现象，影响正常工作。本文以某型1.65MW水平轴风力机叶片为研究对象，采用ANSYS和CFX弱耦合的方式对不同环境下的叶片进行流固耦合数值模拟，旨在研究叶片在气动载荷和结构体相互作用下的受力和稳定特性。论文的主要工作如下： (1)建立了风力机叶片的几何外形和有限元模型。在此模型基础上，模拟静力测试试验，进行模态分析，通过与实验数据对比，证明了模型的有效性，较好的模拟了叶片的真实结构。 (2)提出用CFX和ANSYS求解的流固耦合方案，通过方柱薄板绕流振动算例计算与实验结果相比较，验证该耦合方法的可靠性。采用此耦合方法研究了风力机叶片在恒定风速工况下的受力和稳定性特性，并与未耦合条件下的计算结果进行了对比。结果表明，叶片在耦合作用下表面压力差沿展向逐渐增大，在与结构体的耦合作用下导致叶片振动、变形，，振动形式符合模态分析结果。 (3)对阵风和暴风复杂环境下的叶片进行了稳定性分析。建立了周期性极端阵风和随机阵风的数学模型。采用ANSYS/CFX流固耦合方法数值研究了三种复杂风速环境（即周期性极端阵风、随机阵风和暴风）下的风力机叶片受力和稳定性，分析了叶片的振动过程。通过这三种工况的对比研究，发现叶片的振动形式以一阶挥舞形式为主，叶片的位移沿展向逐渐增大且叶尖附近变化最为显著。叶片表面的应力主要集中在叶展中部位置，为叶片的安全性考虑，此处结构的强度应加强。
[Abstract]:Wind turbine blade is one of the important components of wind turbine. With the large scale of wind turbine and the increasing of blade scale, the unstable phenomena such as structural vibration and deformation will occur when the large wind turbine is operating in gusts and storms, which will affect the normal operation of the wind turbine. In this paper, the fluid-solid coupling numerical simulation of a 1.65MW horizontal axis wind turbine blade under different environments is carried out by using ANSYS and CFX weak coupling method. The purpose of this paper is to study the force and stability characteristics of blades under aerodynamic loading and structural interaction. The main work of this paper is as follows: (1) the geometry and finite element model of wind turbine blade are established. On the basis of the model, the static test is simulated and the modal analysis is carried out. The validity of the model is proved by comparing with the experimental data. The real structure of the blade is well simulated. (2) the fluid-solid coupling scheme solved by CFX and ANSYS is proposed. The reliability of the coupling method is verified by comparing the numerical results of the flow vibration around a square column thin plate with the experimental results. This coupling method is used to study the force and stability characteristics of wind turbine blades under the condition of constant wind speed, and the results are compared with those under uncoupled conditions. The results show that the surface pressure difference of the blade increases gradually along the spanned direction under the coupling action, which results in the blade vibration and deformation under the coupling action with the structure. The vibration form is consistent with the modal analysis results. (3) the blade stability under the complex gusts and storm conditions is analyzed. The mathematical models of periodic extreme gusts and random gusts are established. The force and stability of wind turbine blades under three complex wind speeds (i.e. periodic extreme gusts random gusts and storm winds) are numerically studied using ANSYS/CFX fluid-solid coupling method and the vibration process of the blades is analyzed. Through the comparative study of the three working conditions, it is found that the vibration form of the blade is dominated by the first order wave form, the displacement of the blade increases gradually along the span direction and the change near the tip of the blade is most remarkable. The stress on the surface of the blade is mainly concentrated in the middle part of the blade extension, so the strength of the structure should be strengthened for the safety of the blade.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM315

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