TWO-DIMENSIONAL SIMULATION OF THE FLOW AROUND A THREE-STRAIGHT BLADED VERTICAL-AXIS WIND TURBINE FOR DIFFERENT PITCH ANGLES

This two-dimensional Computational Fluid Dynamics (CFD) study, investigates the effect of blade pitch angle on the performance of a vertical-axis wind turbine (VAWT). The research is focused on the analysis of the variations in blade aerodynamic loads and blade-wake interactions for different blade pitch angles. The CFD model deals with a three-straight-bladed VAWT based on NACA-0015 profiles. The rotor has a diameter of 0.75 m with a chord-to-diameter ratio of 0.16. Blade pitch angles, ranging from 8 degrees toe-in to 6 degrees toe-out, have been investigated using Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations at a fixed diameter-based Reynolds number of 5 center dot 10(5). The results show that modifying the blade pitch angle, impacts the flow around the blades and the blade aerodynamic loads, altering overall turbine performance. Adjusting the blade pitch angle from 0 degrees to 2 degrees toeout, led to a significant increase (over 6%) in the turbine power coefficient (Cp). However, a further increase in the pitch angle leads to a gradual power coefficient decrease. We show that the results, obtained using a two-dimensional CFD model, allow to describe the main features observed in this type of problems.