Study On Design And Performance Analysis Of Horizontal Tidal Turbine

In all kinds of renewable energy, tidal has caught eyes of researchers from many countries for its inherent advantages. Compared with wind energy, tidal energy has higher density. And its periodicity makes the harness easier to conduct. Tidal energy plays an important role in solving global energy problems. And horizontal turbine is one of the most common and efficient equipments in harnessing tidal energy.Tidal turbine shares the same working principle with wind turbine. And Blade element momentum which is adopted in wind turbine design can also be used in tidal turbine design.Since the huge difference in working environment, tidal turbine tends to suffer more loads.Besides, cavitation may occur under high rotating or tidal speed. So this paper focuses on the design of tidal turbine which can meet demands in power output and structure safety as well.The last chapter is the research of promotion in hydrodynamic properties, and the double-blade model is proved to be efficient in improving turbine's work performance.In this paper, CFD method is adopted to predict turbine's work performance. A rotating domain is built to simulate turbine's rotation, and slip mesh is used in dealing with interface.In cases that gravity is ignored, calculation can be conducted in one third models, thus mesh number will decrease significantly. Turbulence model has an obvious effect on calculation results, and it should be chosen according to the flow properties. Ryleigh pleasset model is adopted in the cavitation calculation, and water depth tidal speed and rotating speed are the major concern in the analysis. In the study of double-blade model, structure design is based on its hydrodynamic properties, and calculation methods are the same with single blade model.Calculation results in the paper show that: blade element momentum is viable in tidal turbine design, tip and hub factors can improve the design accuracy; cavitaiton should be taken in consideration for turbines that have a high rated working speed; double-blade model is powerful in improving power output.