碩士 / 國立臺灣海洋大學 / 系統工程暨造船學系 / 101 / In this thesis, the hydrodynamic performance of the horizontal axis marine current turbine and the shrouded current turbines are analyzed and compared by computational methods. The reason to adopt a shroud outside the current turbine is to increase the inflow speed of the current turbine in the Kuroshio, and therefore to achieve a higher power. The effects of different shroud geometries are also investigated in the thesis by computations. Two different computational methods used are the potential flow boundary element method and the viscous flow RANS method. The potential flow boundary element method is a perturbation potential based method, and a wake alignment numerical scheme is established for the current turbine. The computational results are compared to the viscous flow RANS method, and the results are very close. Regarding the shroud design, the computational results of a single shroud indicate that the mass flow into the shroud and inflow velocity of the current turbine can be both increased by increasing the diffuser area ratio. However, the flow field will be influenced by the action of current turbine, and the performance trend will be different from considering the shroud alone. The design of shrouded current turbine thus has to include the action of current turbine, and computational results show that a current turbine with a shroud can provide a higher power. A design procedure similar to the propeller designs is also presented in the thesis. In this procedure, the lifting line method with the Lagrange multiplier method is used for the design of the optimum circulation distribution, and the lifting surface method is adopted for the blade geometry design. Both the BEM and RANS methods can then be used to verify the designs. The design examples show that the developed design procedure is applicable, and can be used for the current turbine blade designs in the future.
| Identifer | oai:union.ndltd.org:TW/101NTOU5345017 |
| Date | January 2013 |
| Creators | Yu-Siou Luo, 羅鈺琇 |
| Contributors | Ching-Yeh Hsin, 辛敬業 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 84 |
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