| At present, the development of marine power generation technology in China has received strong support from the state and local government. As one kind of marine power generation, the tidal current energy generation has important significance in study. As one kind of Tidal current energy generation, the generation technology based on oscillating hydrofoil still has much room for improvement, In order to develop the power generation device with good comprehensive performance, high efficiency and good water power performance, we need to carry out more in-depth hydrodynamic performance analysis.The advantages of oscillating hydrofoil capture tidal power device can be well adapted to the shallow sea area, so it can be better installed in the area along the coast, and even can be installed in the riverbed. Under the same circumstances, the sweep area of oscillating hydrofoil is 2-3 times of the horizontal axis impeller. The single generator power is bigger and the energy efficient is higher. In order to develop the tidal energy resources in the shallow water, the study of the oscillating device is very important.The hydrofoil motion can be decomposed for pitching motion and lift heavy motion coupling and double hydrofoil system can achieve two hydrofoil lift heavy-pitch motion coupling, and it can realize the hydrofoil self- starting, self- sustained oscillation, the kinetic energy of the flow is converted into mechanical energy, and then converted into the electric energy of the generator.In order to obtain the ideal structural parameters of the trapping device, the following work is carried out in this paper:This paper introduces the working principles of an energy-extraction system based on double coupled oscillating hydrofoil in detail. Then systematic explain how to achieve self-starting, Self-sustaining oscillations and how to heave pitch-motion of two hydrofoils coupled to a freedom movement. And it gives the main parameters to measure the capture energy efficiency of double hydrofoil.There is numerical simulation the unsteady flow field of two-dimensional oscillating hydrofoil. And analysis hydrodynamic and capture energy performance in different conditions. Most research is focused on the research at low Reynolds number and flow structure interaction analysis, this thesis study hydrodynamic and capture energy performance of double coupled oscillating hydrofoil under excessive Reynolds and high Reynolds, establish a numerical model about pitch-heave motion of hydrofoil oscillation, then get parameters and algorithms set by Unsteady incompressible NS equations to solve two-dimensional turbulent flow field around the hydrofoil, and also get the algorithm to control hydrofoil border movement based on UDF.The study in this paper of hydrodynamic of the double hydrofoil and capture performance mainly focuses on influence of key parameters on the system’s performance, such as reduced frequency, pitch amplitude hydrofoil profile, Reynolds number and so on. And also make research on changes rule of the hydrofoil lift, drag, pitching, catching power, energy efficiency under various parameters. Then, get the parameter values achieve the best water power and a hydrofoil performance.The hydrodynamic and capture performance of the double hydrofoil meets the high comprehensive performance as hydrofoil profile of NACA0015,a reduced frequency of 0.14,a pitching amplitude of 75°, a Reynolds number is equal to 500 000 or higher, and a phase difference between the pitching and heaving motions of 90°.And in that case, the capture efficiency can achieve 40%.This paper has important guiding significance for the development of tidal current energy generation system based on double oscillating hydrofoil... |
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