| Nowadays,wind turbine is in the atmospheric boundary layer,the inhomogeneous and unsteady flow in the atmospheric boundary layer directly affects the power generation quality of the wind turbine and it has a great influence on the stability and safety of wind turbine blade.The unsteady load of the wind turbine caused by the atmospheric boundary layer and the vibration of wind turbine blade,these two key physical processes are critical to wind turbine safety.In order to study the interaction between atmospheric boundary layer and the downstream blunt body.In this paper,the experimental and numerical simulation method was adopted to study the aerodynamic response of the downstream blunt body under different atmospheric boundary conditions,which analyzes the influence of different atmospheric boundary layer configurations on velocity,turbulence intensity,vortex frequency and dissipation in the wake.In addition,dynamic analysis of first order natural frequency and stress stiffening towards the blades can be researched by combining three types of typical internal structure in order to find a internal structure of blade which can avoid resonance and has better stiffness.On these bases,this paper mainly completed the following aspects of work:1?The roughness elements and spires have been set in the wind tunnel to generate atmospheric boundary layer,and the passive simulation of atmospheric boundary layer has been done in the wind tunnel.The results show that the near-field turbulence generator can simulate the velocity distribution and turbulence state of near-surface atmospheric boundary layer.2?Based on the above atmospheric boundary layer,we put a blunt body(square cylinder)as a model of wind turbine,which simulates the impact of the atmospheric boundary layer on the downstream wind turbine.3?Based on the analysis of velocity pulsation data,the Taylor microscale and turbulent dissipation rates of 8 configurations are studied respectively,and the reason causing the difference of turbulence dissipation rate between 8 configurations is summarized.4?The above experiment was calculated by method of computational fluid dynamics.The velocity and turbulence intensity distributions of numerical simulation are basically consistent with the distribution of experiment.What's more,the result shows that the reason of low velocity at a particular point is due to the vortex happening at the edge of square cylinder.5?The influence of the natural frequency of the blade with different thickness of composite material is studied by method of numerical calculation in this paper.Based on the difference of blade's section,the analysis of stress stiffening towards the blades can be studied by combining the composite lamination.The results show that when the laminate angle of biaxial glass fiber is 45 degree,the first natural frequency achieves the maximum and the laminate angle of composites has great influence on the blade with circle web in the three blade models.In this paper,we mainly use the method of experiment and numerical simulation to study the two important problems that affect the safety wind turbine blade.Firstly,flow field disturbance is caused by the fluctuation of the aerodynamic load.Secondly,the vibration of the blade is affected by the internal structure and the composite material.The previous problem involves unsteady,inhomogeneous and intertwined high turbulent flows and the latter problem involves composites and stress stiffening.Because of the limitation of capacity and time,this paper may have some questions,please forgive the author,and welcome the modification from the experts. |
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