CFD predictions of NREL Phase VI Rotor Experiments in NASA/AMES Wind tunnel

Abstract

Abstract- This article presents the computational predictions of NREL Phase VI rotor, a stall-regulated two bladed wind turbine with full-span pitch control and a power rating of 20 kW, in the NASA/AMES 80 ft. X 120 ft. wind tunnel. A 3D CFD-RANS approach is used, modeling single blade of the rotor utilizing periodicity, in a rotating frame of reference; over several upwind cases. All the simulations are performed using the commercial multi-purpose CFD solver ANSYS CFX 12.1. The blade is modeled with simplified spherical hub excluding nacelle and tower, at stationary wind conditions neglecting wall shear effects due to tunnel blockage. The comparisons are done for the blade with 0 ° yaw angle and 3 ° tip pitch angle. Reasonably good agreement is obtained when comparing modeled mechanical effects Viz. power, thrust, and span wise force components with measurements over wind speeds ranging from 5m/s to 25m/s. The capability of CFD in predicting complex 3D wind turbine aerodynamics is demonstrated in this paper with NREL Phase VI data campaign as a case study.