Investigations on Blade Tip Tilting for Hawt Rotor Blades Using CFD

Abstract

The main purpose of this paper is to study the aerodynamic effects of blade tip tilting on power production of horizontal-axis wind turbines by using Computational Fluid Dynamics (CFD). For validation and as a baseline rotor, the NREL Phase VI wind turbine rotor blade is used. The Reynolds-Averaged Navier–Stokes Equations are solved and different turbulence models including the Spalart–Allmaras, Standard k-ϵ, k-ϵ Yang–Shih and SST k–ω models are used and tested. The results are shown in terms of power generation at different wind speeds and the pressure distribution at different sections of the blade, and the comparisons are made with the available experimental data. For tip tilting analysis, 16 different geometries belonging to four different configurations are studied. The geometries are generated based on changing the twist and the cant angles of the winglet. The four different configurations are obtained from tilting the blade tip toward pressure side, suction side, leading edge, and trailing edge. The effect of the different configurations on the flow characteristics and hence on the power production of the wind turbine is investigated.

Keywords:

• Wind turbine
• HAWT
• Tip tilting
• Winglet
• CFD

Acknowledgments

Monier Elfarra is very grateful to TUBITAK–Bilim Insani Destekleme for granting him a PhD fellowship during his PhD studies. All authors would like to thank NREL for providing the experimental data for comparison of the test case results.