| In this thesis,we design the blade of 1.5MW,3MW and 5MW horizontal axis wind turbine.Conduct modal analysis for the blade of three different megawatt wind turbine. Then,the research works on 5MW horizontal axis wind turbine,conduct simulation for three-dimensional flow field and unidirectional fluid solid coupling of wind turbine. Finally,the thesis investigates modal characteristics of 5MW horizontal axis wind turbine.The studies mainly consist of following aspects:1. Based on the BEM thorem, considering Tip loss model of the blade, using wilson method,the article carries on the design calculation of aerodynamic shape for the blade of 1.5MW,3MW and 5MW horizontal axis wind turbine,obtains geometric parameters of blade,such as the twisting angle and the chord length.2. Through transformation of coordinates,transform geometric parameters of blade designed to the data for three-dimensional space.using Pro/E,we complete the modeling of the blade of 1.5MW,3MW and 5MW horizontal axis wind turbine.3. Without external force, conduct modal analysis for the blade of 1.5MW,3MW and 5MW wind turbine. Ensure the structural characteristics of the blade, such as various order modal shape, various order frequency and so on. Study the results of each order modal analysis.The results show that the natural frequency of the blade of three different megawatt wind turbine doesn’t agree to incentive frequency of wind turbulence. From the start run to the normal operation of wind turbine, rotational frequency of rotor also doesn’t agree to the natural frequency of the blade, Resonance will not occur.4. Under the condition of the rated wind speed, the thesis Simulates three-dimensional flow field of 5MW wind turbine,obtains The actual output power and Cp.Design error is in the permitted range and the reason of error is analyzed. Through the simulation and calculation,we obtain distribution of aerodynamic force of blade, distribution of pressure of each section. Then analyse aerodynamic characteristics.The results of analysis show that distribution of aerodynamic force of blade and distribution of pressure of each section agree to work features of wind turbine.5. conduct simulation for unidirectional fluid solid coupling of 5MW wind turbine.Import aerodynamic force calculated in the flow field to geometic model.Then,exert gravity and Rotating centrifugal force on 5MW wind turbine.Through calculation,obtain distribution of equivalent stress and stress intensity.And study distribution of equivalent stress and stress intensity.According to the third strength theory,check the structural strength of wind turbine,we can obtain that the blade can satisfy the requirement of structural strength.6. Conduct modal analysis for 5MW wind turbine in the condition of no external force or aerodynamic force and centrifugal force. Ensure various order modal frequency to provide a reference for further study of structural characteristics of wind turbine. |
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