| Since the last century, with the continuous depletion of fossil energy and the increasing environmental protection requirements, more and more attention from many countries around the world are bei ng paid to developing and utilizing new renewable energy sources. Tidal current energy is a kind of clean, pollution-free, rich and renewable energy sources, which can effectively alleviate the energy crisis. As a tidal energy-catching device, tidal turbine is a key part of tidal power station as well as affects the performance of the whole power system. It is the most basic and most important part of the tidal current energy generating device that the turbine blades is rotated by the lifting force and then drive the generator to generate electricity. In view of the turbine blade belonging to the key components of the turbine to obtain the tidal current energy, the effects of the turbine blade shape device on the energy capture efficiency of tidal turbine is researched to improve the energy conversion efficiency of tidal energy equipment. In this paper, based on the 50W-class tidal turbines blade, the influence of wing fence and wing tip winglet devices on the design of turbine blade is studied with the help of the BEM theory and numerical simulation(CFD) methods.First of all, in terms of the world energy situation, this paper expounds the background and significance of the tidal energy as well as the research on power generation technology. Then, a large number of domestic and foreign relevant information about tidal turbine is reviewed, learn from the successful experience and sum up the problems in research as well as the technical problems. Secondly, the classical BEM theory is introduced, the working pr inciple of turbine is analyzed and the methods of the blade design and its performance are discussed as well as the detailed steps of the blades design are given. Meanwhile, the turbine blade airfoil and influence factors of the dynamic characteristics are introduced and researched, the blades airfoils’ performance is predicted with the CFD method. At the same time, the lift-drag coefficient and lift drag ratio of NACA63-4xx airfoils and the flow field around it are obtained. These results can provide the b asic data for selection of blade section airfoil. Then, with the help of MATLAB, the related parameters of the cross-section airfoil of every blade are calculated and are corrected to make the blade structure smooth. According to the obtained geometric par ameters, the basic solid model of tidal turbine blade was established using the software CATIA basing on the aerodynamic center and its hydrodynamic performance was simulated using CFD method. The contrast between the theoretical calculation results and CD F simulation results verified the validity of the design method of blade;Finally, based on the 50W-class tidal turbines blade basic model, the influence of wing fence and wing tip winglet devices on optimizing the design of turbine blade is studied with th e help of the BEM theory and numerical simulation(CFD) methods. Theoretical analysis results show the correctness and reliability of the turbine model. Numerical simulation results indicate that the wing fence and wing tip winglet devices could improve the energy capture efficiency, and the later is more advantageous to improve the efficiency of turbine energy capture compared with the former. The wing tip not only fast weakens the influence of the vortex on the tail speed of the turbine, but also improves the turbine capacity performance of unit water area, which shows that using it to improve hydrodynamic performance of the turbine is more desirable. |
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