Computational analysis on hydrodynamic performance of cross-H tidal current hydro-turbine

摘要

Tidal current energy is a kind of new renewable energy in ocean.Turbine is the key equipment of tidal current power station.A new type of cross-H turbine is presented in this paper based on research work in traditional vertical axis straight blade hydro-turbine(named single-H turbine).Hydrodynamic performance of this turbine is simulated by commercial software CFX including instantaneous force on the blade and torque and power on the turbine.Three dimensional structural grid and sliding mesh method are used in the computational simulation.Incompressible Reynolds time averaged Navier-Stocks equations combined with SST turbulence model for governing equations and finite control volume method for discretization are used in the computation.Compared with the hydrodynamic performance of single-H turbine,the analyzed results show that cross-H turbine not only has the same advantages with single-H turbine such as straight blade for easy structure,but also has lower load on a single blade.And then torque on main axis of cross-H is more stable than single one.The power coefficient of cross-H turbine is less than that of single-H turbine slightly,but the start-up torque is obvious larger at same lower rotate speed,that is,cross-H has the potential ability to achieve self-start at low ratio of tip-speed.All of above,cross-H turbine is a better type for mechanical and structural design of the collecting energy device and better application for real tidal current power station.