The Blade Design And Experimental Study On Horizontal Axis Turbine Driven By Tidal Current Energy

In recent years, more and more attentions are being paid on how to extract energy from tidal current, a source of renewable power. Horizontal axis turbine, the uppermost form for utilization of the tidal current energy, harnesses kinetic energy and turns it into eclectic power. Blade is the key part of the turbine; its design and hydrodynamic characteristics have great influence on the conversion efficiency of the turbine. The research on designing the blade occupies decisive position in the tidal current turbine designing. Blade element and momentum (BEM) theory has achieved a great success in blade design of propellers and wind turbines. The model test in water tank is an effective and accurate approach that predicts the hydrodynamic performance of the turbine. The paper studies the method to design the blade based on BEM theory and the turbine's hydrodynamic performance by model experiment in water tank. The main contents and conclusions are as follows:By using the method to design the blade of propellers and wind turbines for reference, mathematical model of optimal design of tidal current turbine blade is put out, based on BEM theory, in which loss of the blade root and tip is considered. The design procedures with MATLAB are presented, and parameters of blade used in model experiment are listed out. In order to process and manufacture conveniently, the chord length and torsional angle are modified.In this paper, hydrodynamic characteristics of hydrofoil are analyzed using CFD software Fluent. Different turbulence models are applied in the simulation process and their effects on simulation accuracy are discussed. The force characteristics and flow structure around the hydrofoils, varied with the thickness and camber, are investigated according to the simulation results. They can provide valuable information for the design of the blade.The method is introduced that obtains actual space coordinates of the blade from two-dimensional coordinate of discrete points in the hydrofoils on the coordinate transformation theory. Then, according to the space coordinates, the blades with complex surface are modeled by using 3d modeling software .The testing models of the turbine's blades were manufactured by using Rapid Prototyping technology,and it is blades met the requirements of strength and precision in the experiment process. It provides a new idea to design, model and manufacture the blade.The paper designed water tank model test system and the testing mean of hydrodynamic performances of tidal current turbine. The data of torque, generator power and rotor speed are obtained in different conditions e.g. pitch angles, amount of blades, speed of the flow, are studied by water tank tests. By processing and analyzing the experiment data, the law how these parameters affect the dynamic performances of flexible blade turbine is found. The results provide a guideline to optimization of the blade and engineering application of the turbine.