Three-degree-of-freedom system of linear vibration of blade bending and fluttering of vertical axis wind turbines
| Autor: | Yun-Peng Wu, 吳運鵬 |
|---|---|
| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 Compared to horizontal axis wind turbines, vertical axis wind turbines have the benefit of operation that is independent of the wind direction, lower wind speed to start operation, and less noise. The vibration of blade can be regarded as vibration of a beam. How to support the ends of the beam affect the vibration very much. In this present paper, we start from the energy method of Hamilton’s principle, derive the dynamic governing equations for the blade, which has three degree of freedom (includes bending and fluttering). The key variable to keep the three degree of freedom coupled is the distance from center of gravity to shear center,. When the cross-section of blade is symmetrical, the value of is zero, which means the three degree of freedom will decouple. We creat the model of NACA0015 small size blade. The NACA series blades are asymmetric, so we can keep the three degree of freedom coupled in calculation. We discrete the space and governing equation by finite difference method, solve the cases of simply support and fixed support, respectively. Then use ANSYS Workbench to do the modal analysis. Thus we obtain the natural frequency and mode shape of theory and simulation, respectively. The two results are similar in low frequency mode. By the way we use in this study, we can vary the natural frequency while design the blade, avoiding resonance in operation. Otherwise, we also do the modal testing of small size NACA0015, expect to compare the result of experiment and simulation. Due to the lack of experimental equipment, the boundary conditions of the modal testing can not coincide with the simulation. Finally we build an experiment process only, without data to compare with simulation. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|