Aeroelastic Analysis Of Blades In Vertical Axis Wind Turbine

With the sustaining development of economy and technology, the production and life of mankind are disturbed by energy crisis, which also results in the serious environmental pollution and exacerbation of environment. As an important renewable energy, the exploitation and utilization of wind energy have been paid much attention in the new energy researches. Through the unremitting effort of several years, the research of large-scale wind turbine in our country has had prodigious progress, but yet it has a long way to go.As an important part of wind turbine, the blades bear the most complex loads and they are the most difficult to design in the wind turbine. As a kind of elastic object, the blades may distort or move in the airflow. Meanwhile, the distortions or movements of the blades impact the aerodynamics and change the magnitude and distribution of the loads when the airflow passes around the surfaces of the blades. In this situation, the structure may become unstable under the coupling effect of aerodynamics, inertial and elastic force, and it will influence the normal running of the wind turbine, even cause the serious consequence that the part and complete blades are damaged. Hence the aeroelastic problem of wind turbine is an important problem which relates the safety and reliability of the wind turbine.In the dissertation, the basic theory of space beam element is applied to model the vertical wind turbine by finite element method. Meanwhile, considering the unsteady aerodynamic forces and moments, the aeroelastic equations of the whole wind turbine are established. By employing the basic theory of vibration mechanics, an realization method of Theodorsen unsteady aerodynamics is gained, which is based on element Matrix27 in ANSYS software. The aeroelastic analysis of a simple cantilever beam which is in uncompressible flow is carried out by parametric language APDL. And the result is compared with that is gained by MSC.FlightLoads software, then the rationality of realization method is validated. At last, take the initial design of 1MW vertical axis wind turbine for example, and establish the aeroelastic equations of the whole wind turbine. The basic vibration characteristic parameters of whole structure are obtained through the analysis. By tracking the participant mode with increased rotary speed, the diagram of complex eigenvalues of participant mode versus rotate speed can be plotted. According to eigenvalue criterion of aeroelastic stability, the critical rotate speed can be made out, and it will offer valuable reference for the further design of the windturbine.