Computation of Aerodynamic Load(s) Induced Stresses on Horizontal Axis Wind Turbine Rotor Blade with Distinct Configurations

Abstract

The kinetics of wind turbine blade operation in a wind field domain is complex, as rotor blades in attempt to overcome the aerodynamic loads (drag and wake) counteracting the motion of the blade undergo deflections due to induced stresses. In this study, blade tip deflections and induced stresses on NACA 4610 horizontal wind turbine airfoil were investigated at different wind speeds for three (3) different blade configurations (hollow with spar, hollow no spar and solid configuration), to determine rotor configuration with optimum service performance. Using QBlade v0.8, aerodynamic load induced stresses were computed for normal and tangential loads at wind speeds of 2, 4, 6 and 8 m/s for three horizontal axis wind turbine rotor blade configurations namely: hollow with spar, hollow no spar and the solid configuration. The blade tip deflections as well as the resultant fatigue stress for both x and z axis at wind speeds of 2, 4 6 and 8 m/s were observed to increase proportionately with the wind speeds. Within a wind speed of 2-8 m/s, tip deflections increased from 5.8203e-03 to 0.2873 mm and 0.5700 to 1.7347 mm on the x and z axis, while the resultant fatigue stresses also increased from 2.77 to 8.19 MPa for the hollow blade configured with spar. The tip deflections also increased from 5.86483e-03 to 0.2971 mm and 0.589 to 1.7900 mm on the x and z axis with resultant fatigue stresses from 2.88 to 8.54 MPa for hollow blade configured with no spar. Similarly for the solid blade configuration at wind speed of 2-8 m/s, the tip deflections increased from 3.530097e-03 to 0.180601 mm and 0.363439 to 1.09563 mm with resultant fatigue stresses also increasing from 1.91 to 5.55 MPa. Maximum von-Mises stresses recorded along the blade radius occurred at the mid-section (1.2 m), and were 5554030, 81898880 and 8536480 Pa for solid, hollow with spar and hollow with no spar. The solid blade configuration produced the lowest blade tip deflections, fatigue stresses and von-Mises stresses, indicating that it has a higher load bearing capacity than hollow blade with spar and hollow blade with no spar.

Keywords

• Wind Turbine
• Spar
• Tip Deflection
• von-Mises Stress
• Blade Configurations
• Aerodynamic Loads

References

1. Brøndsted, P. & Nijssen, R. (2013). Advances in Wind Turbine Blade Design and Materials. Woodhead Publishing, Oxford, UK, 484 p.
2. Ebunilo, P. O., Ikpe, A. E. & Owunna, I. (2016). Determining the Accuracy of Finite Element Analysis when Compared to Experimental Approach for Measuring Stress and Strain on a Connecting Rod Subjected to Variable Loads. Journal of Robotics, Computer Vision and Graphics, 1(1), 12-20.
3. Efe-Ononeme, O. E., Ikpe, A. E. & Ariavie, G. O. (2018). Thermo-Structural Analysis of First Stage Gas Turbine Rotor Blade Materials for Optimum Service Performance. International Journal of Engineering and Applied Sciences, 10(2), 118-130.
4. El Khchine, Y., Sriti, M. & Elyamani, N. E. (2019). Evaluation of Wind Energy Potential and Trends in Morocco. Heliyon, 6(6), 18-30.
5. Etuk, E. M., Ikpe, A. E. & Adoh, U. A. (2020). Design and Analysis of Displacement Models for Modular Horizontal Wind Turbine Blade Structure. Nigerian Journal of Technology, 39(1), 121-130.
6. Etuk, E. M., Ikpe, A. E. & Ndon, A. E. (2021). Modal Analysis of Horizontal Axis Wind Turbine Rotor Blade with Distinct Configurations under Aerodynamic Loading Cycle. Gazi University Journal of Science Part A: Engineering and Innovation, 8(1), 81-93.
7. Hogg, P. (2010). Wind Turbine Blade Materials. SUPERGEN Wind Phase 1 Final Assemble, University of Loughborough, March 25th, 2010. Engineering and Physical Science Research Council.
8. Ikpe, A. E., Owunna, I., Ebunilo, P. O. & Ikpe, E. (2016). Material Selection for High Pressure (HP) Turbine Blade of Conventional Turbojet Engines. American Journal of Mechanical and Industrial Engineering, 1(1), 1-9.

9. Ikpe, A. E., Orhorhoro, E. K. & Gobir, A. (2017a). Design and Reinforcement of a B-Pillar for Occupants Safety in Conventional Vehicle Applications. International Journal of Mathematical, Engineering and Management Sciences, 2(1), 37-52.
10. Ikpe, A E., Owunna, I. B. & Satope, P. (2017b). Design optimization of a B-pillar for crashworthiness of vehicle side impact. Journal of Mechanical Engineering and Sciences, 11(2), 2693-2710.
11. Ikpe, A. E. & Owunna, I. (2017). Design of Vehicle Compression Springs for Optimum Performance in their Service Condition. International Journal of Engineering Research in Africa, 33, 22-34.
12. Lee, J. K., Park, J. Y., Oh, K. Y., Ju, S. H. & Lee, J. S. (2015). Transformation Algorithm of Wind Turbine Blade Moment Signals for Blade Condition Monitoring. Renewable Energy, 79, 209-218.
13. Mishnaevsky, L., Branner, K., Petersen, H. N., Beauson, J., McGugan, M & Sørensen, B. F. (2017). Materials for Wind Turbine Blades: An Overview. Materials, 10(1285), 1-24.
14. Okokpujie, I. P., Okonkwo, U. C., Bolu, C. A., Ohunakin, O. S., Agboola, M. G. & Atayero, A. A. (2020). Implementation of Multi-criteria Decision Method for Selection of Suitable Material for Development of Horizontal Wind Turbine Blade for Sustainable Energy Generation. Heliyon, 6, e03142.
15. Owunna, I. B. & Ikpe, A. E. (2019). Evaluation of induced residual stresses on AISI 1020 low carbon steel plate from experimental and FEM approach during TIG welding process. Journal of Mechanical Engineering and Sciences, 13(1), 4415-4433.
16. Owunna, I., Ikpe, A. E. & Achebo, J. I. (2018). Temperature and Time Dependent Analysis of Tungsten Inert Gas Welding of Low Carbon Steel Plate using Goldak Model Heat Source. Journal of Applied Science and Environmental Management, 22(11), 1719-1725.
17. Oyewole, J. A. & Aro, T. O. (2018). Wind Speed Pattern in Nigeria (A Case Study of some Coastal and Inland Areas). Journal of Applied Science and Environmental Management, 22(1), 119-123.
18. Sutherland, H. J. (2000). A summary of the Fatigue Properties of Wind Turbine Materials. Wind Energy, 3, 1-34.