Analysis Of Aerodynamic Performance And Structural Dynamic Characteristics For Horizontal Wind Turbine

Wind turbine is a device for extracting energy from wind which often operates ina negative environment where strong flow fluctuations due to the nature of the wind.Hence，there is an increasing need for computational and experimental procedures forwind-resistant analysis of wind turbine. The fundamental wind-resistant analysis ofwind turbine is airodynamic and structural dynamic analysis．This paper mainly deals with two aspects：One aspect is the Computational Fluid Dynamics(CFD)simulation of the externalflow around wind turbine．Firstly，the fundamental mathematical and mechanicaltheories of CFD are introduced；secondly the characteristics of the commercial CFDsoftware Fluent are outlined；Finally，the external flow of a33kW horizontal windturbine at three different speeds are simulated using Fluent．The results show that lowpressure mainly concentrated in the half upper of the suction surface and highpressure concentrated in the half upper of the pressure surface near the leading edgein the three-dimensional rotation. And with the increasing of the wind speed，thepressure in suction surface decreases while the pressure surface increases. Besides，the pressure calculated agrees well with the experimental values in the cross sections，which means that the calculation method in this paper is feasible.The other aspect is structural dynamic characteristics analysis of rotor blade.Numerical computations are performed using CFX and the pressure distribution willbe transmitted to rotor surface through Workbench data interface platform to makeStatic Structural Analysys. Then the parameters of modes and natural frequencies arestudied under prestressed conditions. Compared to the modal results of staticstructure， the mode frequencies have a slight increase when considering rotaryprestress and fluid-solid coupling effects. It indicates that the role of the external flowfield and the rotating prestress will change the dynamic characteristics of rotor andproduce a more significant prestressed effect. To explore how the natural frequencychanges in different conditions，this paper explores three different speed of the windwheel. Though the analysis and comparison，it is founded that the natural frequencyincreases as the rotor speed increases.