Hydrodynamic Experimental Study on New Type of Vertical-Axis Variable-Pitch Turbine

摘要

Hydrodynamic experiments on spring-controlled passive variable-pitch hydroturbine for tidal stream energy conversion were carried out to seek a new type of higher power coefficient vertical-axis rotor and probe into the appropriate controlling mechanism of blades. The experimental results show that the optimum install position of the blade axis is one fifth of chord from leading edge;the larger is the swing angle of blade, the higher is the power coefficient. This suggests that in the design and manufacture process, there is need of less limitation on the swing angle. For this type of turbine, spring with higher stiffness should be chosen relative to incoming velocity, fluid density and chord length of blade. Flow guide equipment can intensify the flow velocity and stability of working flow field, which leads to power coefficient improvement. Using concave flow guide dome with back expand shape, the improvement of power coefficient is remarkable.