Aerodynamic analysis of backward swept in HAWT rotor blades using CFD


Article Metrics: (Click on the Metric tab below to see the detail)

Article Info
Published: 15-12-2018
Section: Original Research Article
Fulltext PDF Tell your colleagues Email the author

The aerodynamical design of backward swept for a horizontal axis wind turbine blade has been carried out to produce more power at higher wind velocities. The backward sweep is added by tilting the blade toward the air flow direction. Computational Fluid Dynamics (CFD) calculations were used for solving the conservation equations in one outer stationary reference frame and one inner rotating reference frame, where the blades and grids were fixed in reference to the rotating frame. The blade structure was validated using Reynolds Averaged Navier-Stokes (RANS) solver in a test case by the National Renewable Energy Laboratory (NREL) VI blades results. Simulation results show considerable agreement with the NREL measurements. Standard K-ε turbulence model was chosen for simulations and for the backward swept design process. A sample backward sweep design was applied to the blades of a Horizontal Axis Wind Turbine (HAWT) rotor, and it is obtained that although at the lower wind velocities the output power and the axial thrust of the rotor decrease, at the higher wind velocities the output power increases while the axial thrust decreases. The swept blades have shown about 30 percent increase in output power and about 12 percent decrease in thrust at the wind speed of 14 m/s.


Horizontal Axis Wind Turbine; CFD; Backward Sweep;Wind Turbine Efficiency;Blade shape Optimization

  1. Mohammad Sadegh Salari 
    Department of Energy Engineering, Sharif University of Technology, P.O. Box 14565-114, Tehran, Iran, Islamic Republic of
  2. Behzad Zarif Boushehri 
    Department of Aerospace Engineering, Sharif University of Technology, P.O. Box 11155-11365, Tehran, Iran, Islamic Republic of
  3. Mehrdad Boroushaki 
    Department of Energy Engineering, Sharif University of Technology, P.O. Box 14565-114, Tehran, Iran, Islamic Republic of
  1. AbdelSalam, A. M., Ramalingam, V., (2014) Wake prediction of horizontal-axis wind turbine using full-rotor modeling, J. Wind Eng. Ind. Aerodyn., vol. 124, pp. 7–19.
  2. Balduzzi, F., Bianchini, A., Maleci, R., Ferrara, G., Ferrari, L. (2016) Critical issues in the CFD simulation of Darrieus wind turbines,” Renew. Energy, vol. 85, pp. 419–435.
  3. Betz, A. (2014) Introduction to the theory of flow machines, Pergamon Press.
  4. Cao, L., Ji, Y., Wang, Z., Yuan, W. (2012) Analysis on the influence of rotational speed to aerodynamic performance of vertical axis wind turbine, Procedia Eng., vol. 31, pp. 245–250.
  5. Chattot,, J. J. (2009) Effects of blade tip modifications on wind turbine performance using vortex model, Comput. Fluids, vol. 38, no. 7, pp. 1405–1410.
  6. Elfarra , M. A., (2011) Horizontal Axis Wind Turbine Rotor Blade: Winglet and Twist Aerodynamic Design and Optimization Using CFD, Middle East Technical University.
  7. El-Wakil , M. M. (1984) Power plant Technology. McGraw-Hill International.
  8. Farrugia, R., Sant,T., Micallef, D. (2016) A study on the aerodynamics of a floating wind turbine rotor, Renew. Energy, vol. 86, pp. 770–784.
  9. Gaunaa, M., Johansen, J. (2007) Determination of the maximum aerodynamic efficiency of wind turbine rotors with winglets, Journal of Physics: Conference Series, Vol. 75, p. 012006.
  10. Giguere, P., Selig, M. S. (1999) Design of a tapered and twisted blade for the NREL combined experiment rotor, NREL/SR, vol. 500, p. 26173.
  11. Janajreh, I., Qudaih, R., Talab,, I., Ghenai, C. (2010) Aerodynamic flow simulation of wind turbine: downwind versus upwind configuration,” Energy Convers. Manag., vol. 51, no. 8, pp. 1656–1663.
  12. Jeon, M., Lee, S. (2014) Unsteady aerodynamics of offshore floating wind turbines in platform pitching motion using vortex lattice method, Renew. Energy, vol. 65, pp. 207–212.
  13. Li, Y., Paik, K. J., Xing, T., Carrica, P. M. (2012) Dynamic overset CFD simulations of wind turbine aerodynamics,” Renew. Energy, vol. 37, no. 1, pp. 285–298.
  14. Make, M., Vaz, G. (2015) Analyzing scaling effects on offshore wind turbines using CFD, Renew. Energy, vol. 83, pp. 1326–1340.
  15. Mohamed, M. H., Ali, A. M., Hafiz, A. A. (2015) CFD analysis for H-rotor Darrieus turbine as a low speed wind energy converter, Eng. Sci. Technol. Int. J., vol. 18, no. 1, pp. 1–13.
  16. Subramanian, B., Chokani, N., Abhari, R. S. (2016) Aerodynamics of wind turbine wakes in flat and complex terrains, Renew. Energy, vol. 85, pp. 454–463.
  17. Sedaghat, A., Assad, M. E. H., Gaith, M. (2014) Aerodynamics performance of continuously variable speed horizontal axis wind turbine with optimal blades, Energy, vol. 77, pp. 752–759.