Design and Analysis of Variable-pitch Mechanism of Vertical-axis Tidal turbine

As the kernel part of the vertical-axis tidal turbine, variable-pitch mechanism determines the self-startup ability and energy capture efficiency of the turbine. In order to improve the energy capture efficiency, a variable-pitch mechanism of tidal turbine based on the principle of space lever is proposed. The motion simulation is carried out by using PRO/E. The rationality and correctness of variable-pitch mechanism design are verified by comparing the motion simulation curve with the theoretical diagram. The forces acting on the blades at every position in a rotating cycle with different eccentricity are analyzed by using FLUENT, and the torque of each blade to the center of rotation and its synthetic torque are obtained which provides date for the dynamic analysis of the variable-pitch mechanism. The power bond graph method is used to analyze the dynamic characteristics. It’s proved that the turbine with variable-pitch mechanism has higher energy capture efficiency. The first ten natural frequencies are obtained by model analysis of the key components of the variable-pitch mechanism. By comparing with the tidal load frequency and the impeller rotation frequency, it is proved that there is no danger of resonance in the variable-pitch mechanism of the tidal turbine.