Airfoil Optimization of Vertical-Axis Turbine Based on CFD Method

Vertical-axis turbine (hereafter VAT) is the common and key equipment in tidal-current turbine generator systems in recent years, with the characteristics of the main axis perpendicular to the flow direction, the blade parallel to the main axis. The kinetic energy of water stream is absorbed by VAT, translated into mechanical energy and then into electric energy. The hydrodynamic performance of VAT depends greatly on the airfoil of the rotor´s blade section. Therefore, the output power of VAT can be improved by changing the airfoil of the blades. For this purpose, the flow fields around VAT with different airfoils were numerical simulated by solving Navier-Stokes equations, using sliding mesh model and user-defined functions (UDF) of viscid CFD code FLUENT. And an optimum airfoil was presented. The numerical results show that the power coefficient (Cp) of VAT with the optimum airfoil increased in the operating tip-speed ratio (TSR) region and the peak value was higher nearly 23%.