Research And Design On Small Low Permanent Magnetic Wind Turbine's Blade And Bearing

Wind energy is green and renewable energy. To develop wind energy resources vigorously was a common trend in the case of the world's energy shortages and emphasizing the environmental protection. Reducing the wind turbine's start-up wind speed can fully exploit the wind energy. The blade and the bearing of the shaft was one of the criticality factors which can expanded the utilization of wind resources, so it had practical significance to research the blade of the wind turbine and the supporting way of the shaft.Some design theories of blade was introduced. The Betz theory indicated that the maximum wind energy utilization coefficient of wind turbine was 0.593, Till now there was no wind turbine could exceed this limit. Introduced the blade element theory, derived the force distribution and the axial torque of the element blade by the assumptions. Introduced the vortex theory,vortex theory was derived by the magnetic field theory and the air vortex which through the wheel and above the wheel, the result was equal with the Betz theory.The basic conceptions of the airfoils and the NACA series airfoils and the dedicated airfoils was introduced. The aerodynamic of two kinds of NACA series airfoils was analyzed by the CFD software Fluent, included the comparative analysis of the pressure field, velocity field and the Lift-drag ratio characteristics. The airfoil was improved as to satisfy the requirements of low wind speed start. The appropriate airfoil was determined by the comparative analysis between the NACA airfoil and the improved one. According to the Betz theory, The blade was modeled and element analyzed by used the improved airfoil.The magnetic bearings was used in the small wind turbine to reduced the start moment of resistance of the wind turbine. The influences of the radial force and the axial force by the radial offset was analyzed, the structural design of magnetic bearings was carried on by the analysis results. The influences of the wind turbine start moment of resistance by the magnetic bearing was analyzed through the comparative experiment about two wind turbines which used different kinds of bearing ways. The small magnetic wind turbine was designed, the problems and the solutions when assembling the small magnetic wind turbine was analyzed. As the magnetic rings produced strong magnetic force when assembling, it was necessary to design an assembly mechanism, the assembly process of magnetic bearings was introduced in details. The assembly process of the general was introduced and the structural features of the small magnetic wind turbine was analyzed.