Solving The Limited Vortex Method Of The Airfoil Movement

As renewable energy,the tidal current energy is becoming a hot research topic all over the world. The resource of tidal current energy in china is rich, so its exploitation potentiality is promising. Vertical axis tidal turbine is one of the most widely used devices for tidal current energy conversion in the world. And the deep research of hydrodynamic characteristics of these devices can provide guidance for design more efficient current energy conversion devices which are of great significance to solve the increasingly serious energy and environmental issues. However,the hydrodynamic properties of vertical axis tidal turbine are very complex due to its structure form. And there are many basic problems have not yet been satisfactorily resolved for the fluid dynamics design of vertical axis tidal turbine. Based on National Key Technology Support Program "Research and Demonstration of the key technology of 150kW Tidal Current Energy Plant", this thesis which is aimed at put vertical axis tidal turbine into practice development has used model tests and numerical simulations to study fixed pitch and free variable pitch vertical axis tidal turbine.The working principle, classification and performance characteristics of vertical axis tidal turbine have been described in this paper at first. And the movement and force characteristic of the blades and turbine have been analyzed during running. Then the main factors that affect the characteristics of the turbine were determined by dimensional analysis and the affect of major factors have been preliminarily studied on the hydrodynamic characteristics of the turbine.Paper analyzes the current domestic and international mainstream and the basic principle of vertical shaft power generation device structure,this paper introduces the vertical shaft hydrodynamic performance of the impeller and the progress of the optimization method. And through, the paper's main work is as follows:1. Set up the kinematics and dynamics,the vertical shaft turbine rotor unified defines the geometry,kinematics and turbine kinetic parameters,this paper expounds the working principle of turbine, analyzed the speed ratio and the blade Angle influence on turbine energy utilization.2. On the basis of the vortex surface element method, this paper proposes a new way of singularity distribution, will source and vortex are arranged in the wings .On the surface,with the constant vortex sheet to simulate the trailing vortex shedding, combined with the Kutta condition of single blade unsteady is built up limit vortex model, provides a theoretical basis for optimization of work.3. Using finite vortex method for fixed Angle type turbine and variable Angle type turbine load forecast, through concrete calculation and model test results, verify the accuracy and reliability of the method, finally through the cycloidal variable Angle turbine case pointed out that by changing the blade Angle can improve the energy utilization in the operation process, reduce the load fluctuation amplitude.