Structural Design For The Blade Of Vertical Axis Wind Turbine

The serious crisis consciousness has promoted the development of newenergy. Wind energy becomes one of the most popular new energy. In recentyears, close attention has been paid to the vertical axis wind turbine (VAWT). Atpresent there are no mature VAWT products which are widely used. Blade is oneof the key components of the wind turbine. Its good aerodynamic performancewill ensure the high wind energy utilization of the wind turbine; its goodstructural performance will ensure the safety for the wind turbine to operationnormally and also can largely reduce production cost. On the basis of the goodaerodynamic performance of the blade the structure of the blade is the mainresearch in this paper. The contents are as follows.Firstly, Double-Multiple-Stream Tube model from the Mementum-BladeElement Theory has been used to analyze varied aerofoils which are widely used.Concretely, the relationship between the power coefficient and the tip speed ratioof each aerofoils are mainly analyzed. Then according to the results, the mostsuitable aerofoil has been selected. And the basic parameters of the wind turbinewhich is used to validat the blade performance have been defined.Secondly, a new blade structure has been designed. Its shape is the contourof the selected aerofoil. Its structure is so called frame-skin structure. Theinternal frame structure of the blade is the main load-carrying structure. Theouter skin of the blade provides a smooth aerodynamic shape and the windwardsurface. The internal frame structure supports the skin to ensure the aerodynamicshape. Based on the universal finite element analysis software ABAQUS, theinternal frame structure of the blade has been designed, calculated and optimized.The targets of the optimization are those all of the mass of the blade, themaximum displacement and stress are small. A comparative computationalanalysis has been made between four different kinds of blade structure. Thecomparison result shows that the blade structure designed in this paper has bettermechanical characteristics.Lastly,1MW wind turbine structure has been designed to simulate the actualoperation situation of the blade. In this paper dynamic characteristics of the blade have been calculated and analyzed. The mechanical properties of the windturbine in each limit condition have been studied. And the deformation and stressdistribution about the blade has been focused on. The result shows that thedynamic responses of the blade satisfy requirements of the design code. Becauseof the structural characteristic of the wind turbine of the VAWT, there is a bigdifference between the natural frequency of single blade and the working turbine.So the modal analysis of the wind turbine has been done to study the vibration ofthe blade. The result shows that the blade designed in this paper is not easy to bedamaged for the reason of resonance.