| The wind speed in the low wind speed region is generally small,and the existing wind blades cannot make full use of the wind energy resources in the low wind speed region.Based on the Leaf element momentum theory and the related design a big moment for direct-drive wheel type fan wind vane,start wind speed is low,the characteristics of the torque coefficient is bigger,has good aerodynamic efficiency,and based on blade aerodynamic shape design of the structure strength and structure of blade natural frequency to meet the requirements.1.The related conceptual theories of blades and leaf element airfoils were studied and analyzed,and the influence of relevant parameters of blades and airfoils on aerodynamic performance was analyzed,and the research conclusions of airfoils were verified by Fluent and Profili software.The leaf element momentum theory and its related theories were studied and deduced,and the expressions of inducible factors were derived by combining the correlation loss coefficient and empirical formula.Finally,an iterative calculation method for aerodynamic parameters of blades was designed based on the leaf element momentum theory and its related theories.2.The rated wind speed,starting wind speed and cutting wind speed were selected.Three airfoils with good aerodynamic performance were analyzed,and NACA4415 airfoils were selected.The overall parameters of the blade,such as rated power,blade number,radius,tip speed ratio and chord length,were designed based on blade-related theories.The aerodynamic parameters of each blade element were calculated by using the iterative calculation method combined with profili and MATLAB,and the three-dimensional modeling of the blade was carried out by using the coordinate transformation method.3.The method of blade fluid simulation was analyzed,and the setup flow of blade fluid simulation was designed.Fluent was used to conduct fluid calculation on the three-dimensional model of the blade,and the cloud diagram of simulation results was analyzed.Fluent was used to optimize the tip speed ratio parameters,and the aerodynamic efficiency reached 0.44 when the final tip speed ratio was 2.72.By comparing the torque coefficient of high-speed wind blades and verifying the characteristics of the large torque of this blade,the torque coefficient of this blade is 2.817 times that of the high-speed blade.The power regulation method of blade working wind speed interval is studied and the power rule is calculated by fluid simulation.4.Based on the aerodynamic shape of the blade,the blade material is selected and the blade structure is designed.The strength and rigidity of the blade under the limit condition are calculated by using the fluid structure coupling calculation module of ANSYS.In addition,the vibration modes of different vibration stages of the blade are analyzed by using the modal analysis,and the resonance phenomenon will not occur in the analysis of the natural frequency of the blade. |
