Numerical and experimental validation of vortex generator effect on power performance improvement in MW-class wind turbine blade

Abstract

As blades become larger, performance loss occurs due to separation at the root. In particular, it will become more evident in offshore wind turbines equipped with large blades, and there is a possibility of solving through VG. This test, verified near the shore, can be further utilized at sea. The cost of attaching the VG pairs to the wind turbine blade is high, so it is important to predict aerodynamic performance by CFD analysis. Vortex generators were attached to the blades of a 2.3 MW wind turbine to validate the effect of the VGs on the wind turbine performance. Aerodynamic performance data for two months were measured using Supervisory Control and Data Acquisition and compared with data generated by the blade without VGs during the same period in 2018. As a result, it was confirmed that when VG was attached, the power generation performance was improved at high wind speed, while the performance decreased at low wind speed. The power generation performance of a 2.3 MW wind turbine with VGs was improved by 4.83% at a wind speed of 10 m/s, and the total annual energy production increased by 1.87% for operation in the wind speed range of 4-11 m/s. The VGs were precisely installed with the aid of laser tracking technology to correspond with the locations indicated by the CAE model, which resulted in a maximum error of 0.037%. The attachment coordinates were set by referring to the separation line determined by computational fluid dynamics analysis. The CFD analysis of the 2.3 MW wind turbine blade with VGs was performed using the RANS equation and the CFX package of ANSYS. The CFD results indicated that the torque was increased by 2.80% for the rated wind speed of 10 m/s. In addition, the effect of VGs was investigated by analyzing the vortex behavior and velocity profile of the fluid passing through the VG. The effect of the VGs on the AEP was also calculated using GH-bladed, a tool based on blade element momentum theory for designing wind turbine blades. These results also showed that the VGs improved the AEP by 0.81%.