Jing Jia

The uneven distribution of airflow on the blade surface of a yaw wind turbine triggers a complex non-constant flow, resulting in turbine flow field operation disorder, which, in turn, affects the structural field. In view of the different degrees of influence of different blade materials on the structural characteristics of a wind turbine, a numerical simulation of the flow field and structural field of the horizontal-axis wind turbine under different yaw conditions is carried out by using the fluid–solid coupling method to quantitatively analyse the degree of influence of the material on the structural characteristics of the wind turbine. The results show that the average velocity of the wake cross-section shows a trend of decreasing, then increasing, and then stabilising at all yaw angles. The larger the yaw angle, the wider is the vortex structure dispersion. As the wake develops downstream, the turbulence intensity is shown to decrease and then increase, and the yaw perturbation exacerbates the turbulence disorder in the wake flow field. Along the wind turbine blade spreading direction, the blade deformation phenomenon is significant. The yaw angle increases, the wind turbine blade deformation increases, and the maximum blade stress first increases and then decreases. At a 15° yaw angle, the airflow on the blade surface is more easily separated, and vortices are formed in the vicinity, which impede the airflow in the boundary layer and lead to a reduction in the velocity in the boundary layer in this region. The minimum deformation and maximum stress of the three materials under a 15° yaw angle indicate that the blades are more capable of resisting external deformation under this condition, so 15° yaw is the best operating condition for the wind turbine. This paper employs different materials to quantitatively analyse the extent to which structural characteristics influence wind turbine performance. The findings from this research can provide valuable insights for optimising wind turbine designs.

A wind turbine is a rigid–flexible coupling system, and its blades will be deformed under the action of aerodynamic force, inertia force, and elastic force. To monitor the deformation of the blades, this paper builds a dynamic deformation measurement system for wind turbine blades based on 3D-DIC and directly measures the three-dimensional displacement distribution of different blades under different operating conditions to obtain the dynamic deformation of the blades. The experimental results show that the dynamic waving deformation of the blade shows the trend of increasing and then decreasing with the increase in wind turbine rotational speed and incoming wind speed, and when the rotational speed reaches 500 r/min and the incoming wind speed reaches 9 m/s, the blade deformation reaches the maximum value; the dynamic waving deformation of wind turbine blade decreases with the increase in the elastic modulus of the blade and the degree of the decrease decreases gradually; the dynamic deformation of is predicted by the multiple displacement distribution of different blades under different operating conditions, and is obtained by the fitting of the experimental data. This paper develops a 3D-DIC-based dynamic testing system for wind turbine blades, conducts experimental studies to verify and prove the practicality of the system, and finally obtains the prediction polynomials for the dynamic deformation of wind turbine blades under different operating conditions.

The change in the composite lay-up method affects the blade stiffness, which in turn affects the structural dynamic and aerodynamic characteristics, but the influence law is not yet clear. In this paper, two-way fluid–structure coupling is used to study wind turbine blades with different numbers of lay-up layers. The analysis results show the following: (1) With the increase in the number of pavement layers, the maximum deformation of the blade tip decreases, the magnitude of the decrease also decreases gradually, and the growth trend of deformation along the blade spreading direction is gradually flattened. (2) The maximum stress–strain of the root of the blade gradually decreases, the tip of the blade is the opposite of the blade, the unevenness of the distribution of the stress–strain of the surface of the blade is gradually slowed down, and the concentration area is shifted back. (3) The different numbers of pavement layers affect the turbulence intensity of the blade in the flow field space. Herein, the spatial distribution trend of turbulence intensity in the flow field of wind turbine blades with different numbers of layers is basically the same, and the trend of turbulence intensity changes is gentle when the number of layers is increased. (4) The amount of the tip vortex in the wake stream of the wind turbine decreases, and the decay rate of the center vortex increases. A reasonable lay-up scheme can improve the deformation and stress of the blade, extend the service life of the blade, promote airflow mixing, and enhance the energy conversion efficiency.