Experimental Study On The Wake Effect Of Horizontal Axis Tidal Current Turbine

Tidal current energy is a kind of renewable marine energy with great potential. The technology of tidal current energy power gradually enters commercial application stage from engineering prototype stage. The horizontal axis tidal current turbine is an important form of power device of tidal current energy. In the process of its operation, the velocity and direction of flow is changed through the generator rotor. The influence on the initial velocity is called wake effect. The wake effect of horizontal axis tidal current turbine has an influence on the incident velocity of horizontal axis tidal current turbine and the generator power becomes lower. So the study on the wake effect of horizontal axis tidal current turbine is the foundation of the power plant optimized layout and has important theoretic and practical meaning.The paper presents related concepts and the basic knowledge of horizontal axis tidal current turbine. On this basis, in order to study the factors of the wake effect, experimental scheme is designed. The flume experiment is conducted to investigate the law of the wake velocities which are formed by the interaction between the horizontal axis tidal current turbine and the flow. The variation process of flow velocity is measured under the condition of the different initial velocity, thrust coefficient, turbulence intensity, installation height and topography in the direction and the vertical direction of flow. Wake effect is researched and analyzed on a two-dimensional. The outcomes are drawn as follows:In the direction of flow, the faster the initial velocity is, the larger the convergence value of wake is; the influence scope of the thrust coefficient is within the distance of five times disk diameters. At a distance of fifteen times disk diameters, the wake velocities become stable and the convergence value is identical with the thrust coefficient varying. As the turbulence intensity is larger, the recovery capability of wake flow is bigger. The recovery value of wake flow becomes large as the installation height becomes large. The recovery speed of wake flow becomes large as the topography of rotor center becomes large.In the vertical direction of flow, the scope of the wake effect becomes larger with the initial velocity faster, the influence scope of the thrust coefficient is in the range of four times disk diameters. The influence of turbulence intensity and topography of rotor center is small. The influence scope of the installation height is from one times disk diameter to four times disk diameters.The conclusions about the hydrodynamic characteristic of horizontal axis tidal current turbine presented above are important for optimum design of horizontal axis tidal current turbines. Experimental study on the wake effect of horizontal axis Tidal Current Turbine about multiple factors in two dimensions lays the foundation for further study.