A numerical investigation on the effect of blade tip shapes on power generation of a horizontal axis wind turbine

Document Type : Research Article

Authors

1 Department Aerospace Engineering, Amirkabir University of Technology,Tehran,Iran

2 Department of Aerospace Engineering, Amirkabir University of Technology, Tehran, Iran

Abstract

A way to increase the generated power of an available wind turbine blade without changing its base shape is to add proper add-on to the blade tip. In this paper, seven tip add-ons are added to the blade tip of the NREL Phase VI wind turbine, and their effect on generated power is studied using computational fluid dynamics. Reynolds averaged Navier-Stokes equations are used with k-ω SST turbulence model to simulate the flow over the blade. Results show that the tapered tip add-on does not have a notable effect on generated power, while the shark-tip add-on increases the output power by about 4%, which is a minor increase comparing to the other add-ons. The suction surface and pressure surface winglets (without sweepback) increase the power generated by 5.23% and 9.6% respectively, which shows the superiority of pressure surface winglet over suction counterpart. Afterwards, sweepback is added to winglets, showing 11.87% and 13.25% power increase for suction surface and pressure surface winglets respectively, which shows the positive effect of sweepback angle in generated power increase. This is obtained by only a 28 cm add-on to the base blade with a radius of 553 cm.

Keywords

Main Subjects


[1] M.M. Hand, D.A. Simms, L.J. Fingersh, D.W. Jager, J.R. Cotrell, Unsteady aerodynamics experiment Phase V: Test configuration and available data campaigns, NREL Technical Report-TP-500-29955,  (2001).
[2] D. Simms, S.J. Schreck, M. Hand, L.J. Fingersh, NREL Unsteady aerodynamics experiment in the NASA-Ames wind tunnel: A comparison of predictions to measurements, NREL Technical Report-Tp-500-29494,  (2001).
[3] N.N. Sørensen, J.A. Michelsen, S. Schreck, Navier-Stokes predictions of the NREL phase VI rotor in the NASA Ames 80 ft × 120 ft wind tunnel, Wind Energy, 5 (2002) 151-169.
[4] E.P.N. Duque, M.D. Burklund, W. Johnson, Navier-Stokes and comprehensive analysis performance predictions of the NREL Phase VI experiment, ASME 2003 Wind Energy Symposium,  (2003) 43-61.
[5] Y. He, R.K. Agarwal, Shape optimization of NREL S809 airfoil for wind turbine blades using a multi-objective genetic algorithm, International Journal of Aerospace Engineering, 2014 (2014) 1-13.
[6] M. Kaya, M. Elfarra, Optimization of the taper/twist stacking axis location of NREL VI wind turbine rotor blade using neural networks based on computational fluid dynamics analyses, Journal of Solar Energy Engineering, 141 (2019) 1-27.
[7] M.A. Elfarra, N. Sezer-Uzol, I.S. Akmandor, NREL VI rotor blade: numerical investigation and winglet design and optimization using CFD, Wind Energy, 17 (2014) 605-626.
[8] N. Tobin, A. Hamed, L. Chamorro, An experimental study on the effects of winglets on the wake and performance of a model Wind turbine, Energies, 8 (2015) 11955-11972.
[9] J. Johansen, N.N. Sørensen, Aerodynamic investigation of winglets on wind turbine blades using CFD, Risø National Laboratory-R1543,  (2006) 1-17.
[10] M. Azizi, A. Jahangirian, Multi‐site aerodynamic optimization of wind turbine blades for maximum annual energy production in East Iran, Energy Science & Engineering,  (2020) 2169-2186.
[11] J.E. Bardina, P.G. Huang, T.J. Coakley, Turbulence modeling validation, testing, and development, NASA Technical Report-TM-110446,  (1997).
[12] M.M. Yelmule, E. Anjuri VSJ, C. Author, CFD predictions of NREL Phase VI Rotor Experiments in NASA/AMES Wind tunnel, International Journal of Renewable Energy Research, 3 (2013) 261-269.
[13] N. Zeynali Khameneh, M. Tadjfar, Improvement of wind turbine efficiency by using synthetic jets, ASME 3rd Symposium on the Fluid Dynamics of Wind Energy,  (2016) 1-5.
[14] E. Ferrer, X. Munduate, Wind turbine blade tip comparison using CFD, Journal of Physics: Conference Series, 75(1) (2007) 1-10.
[15] R. Giridhar, Prediction of aerodynamic noise generated by wind turbine blades, M.Sc Thesis-University of  Kansas,  (2016).
[16] K.G.V. Ramachandran, An aeroacoustic analyses of wind turbines, M.Sc Thesis-Ohio State University,  (2011).
[17] M. Ghasemian, A. Nejat, Aerodynamic noise prediction of a horizontal axis wind turbine using improved delayed detached eddy simulation and acoustic analogy, Energy Conversion and Management, 99 (2015) 210-220.