Finite Element Analysis And Type Selection For Blade Structure Of Tidal Current Energy Turbine

As a new kind of renewable energy,tidal current energy has attracted attention from many countries.Blade is an important part of tidal current energy turbine,its performance affect efficiency of turbine directly.A good hydrodynamic performance is the premise of high utilization,and good structure performance is guarantee of safe operation.In this paper,design and selection of blade was carried out according to a 100 kW tidal current energy blade shape which was given.The purpose of the paper is to design a blade with less weight and meet the requirement of strength,stiffness,stability and tidal attack.This paper systematically reviewed the status of domestic and international trend.3types of turbine blades were put forward for horizontal axis marine current turbine based on the blade of wind turbine structure,including metal blade,composite blade,metal frame and composite skin blade.Considering the different material properties,the paper designed different form of internal frame structure,including metal framing blades,web plate and box girder of all composite materials blade,web framing,I beam frame type,metal frame and composite skin of box girder frame blade.In order to make full use of the material,variable thickness gradient design conception along the blade was put forward in the structure.The different blades structure mentioned above were calculated using the finite element software ANSYS Workbench.Various parameters effects on structural mechanics were comparatively analyzed.Finally,the box girder skeleton type metal frame and composite skin of the blade was advised to adopt in practical engineering.To avoid the blade resonate and to ensure the blades local and overall stability,the selected blades were carried out dynamic characteristics analysis.Modal analysis results showed that the modes of blade of low frequency mainly are waving and shimmy,and the natural frequency is far away from the excitation frequency,the blade will not occur resonance destruction.Buckling analysis results showed load subject to blade less than the critical load,the blades will not occur buckling instability.This Structure form and material layout of the proposed blade could effectively reduce the weight of blades and increase the strength and stiffness of blades.Besides,it can provide a reference for future design of similar blades.