Numerical Investigation on the Effect of the Azimuthal Deviation on Performance of Equal Speed Co-Rotating Double Rotor Small-Scale Horizontal-Axis Wind Turbine

Morsi, Ahmed Abdelfattah Abdelwahed; El-Dosoky, Mohamed Fekry Farah; Othman, Othman Hassan; Ahmed, Mohamed Mahmoud Sayed; Ali, Ahmed Hamza Hossieny

doi:10.21608/jesaun.2023.239362.1267

Numerical Investigation on the Effect of the Azimuthal Deviation on Performance of Equal Speed Co-Rotating Double Rotor Small-Scale Horizontal-Axis Wind Turbine

Document Type : Research Paper

Authors

¹ Mechanical Power Dept., Assiut Faculty of Engineering, Assiut University

² a. Department of Mechanical Engineering, Assiut University, 71516 Assiut, Egypt b. College of Engineering, Fahad Bin Sultan University, P.O.B.15700, Tabuk 71454 KSA

³ Mechanical Power Engineering Departmentt,Faculty of engineering,Assiut university.Assiut city,Egypt

⁴ Mechanical Power Engineering Department, Faculty of Engineering, Assiut University, Assiut city, Egypt

⁵ Mechanical Power Department, Faculty of Engineering, Assiut University, Assiut city, Egypt

10.21608/jesaun.2023.239362.1267

Abstract

A double-rotor setup is a promising approach to increase wind turbine power extraction. One common double-rotor configuration is the co-rotating-equal-speed arrangement. The performance of this setup is affected by the azimuthal deviation between the two rotors, which remains constant during rotation. To identify the impact of azimuthal deviation, a numerical investigation was conducted using 10 m/s input wind speed and 0.9 m turbine diameter. The separation distance between the two rotors varied for two values of 0.14 and 0.25 rotor-diameter. The power coefficient of both rotors and the overall turbine were analyzed at different azimuthal deviations using Reynolds-averaged Navier–Stokes k-ω SST equations. The azimuthal deviation was positive when the front rotor preceded the rear and negative when the rear preceded the front. At 0.14 rotor-diameter separation, positive deviation increased the front rotor power coefficient but decreased the rear’s, while negative deviation had the opposite effect on both rotors. The maximum changes in the power coefficient of the front and rear rotors at tip speed ratio of 5 were ΔC_P=0.058 and ΔC_P=0.066, respectively. However, the net harvesting power by the double-rotor wind turbine exhibited slight marginal change of ΔC_P=0.008 at a tip speed ratio of 5. In contrast, at the greater separation, the power coefficients of both rotors and the overall turbine showed slight change with the variation of the azimuthal deviation with a marginal change of ΔC_P=0.012 at a tip speed ratio of 5. Moreover, the highest increase in the power coefficient was 15% compared to single rotor.

Keywords

Main Subjects

Mechanical, Power, Production, Design and Mechatronics Engineering.

References

[1] B. . Newman, “Multiple actuator-disc theory for wind turbines,” J. Wind Eng. Ind. Aerodyn., vol. 24, no. 3, pp. 215–225, Oct. 1986, doi: 10.1016/0167-6105(86)90023-1.

[2] S. N. Jung, T. S. No, and K. W. Ryu, “Aerodynamic performance prediction of a 30 kW counter-rotating wind turbine system,” Renew. Energy, vol. 30, no. 5, pp. 631–644, 2005, doi: 10.1016/j.renene.2004.07.005.

[3] S. Lee, H. Kim, E. Son, and S. Lee, “Effects of design parameters on aerodynamic performance of a counter-rotating wind turbine,” Renew. Energy, vol. 42, pp. 140–144, 2012, doi: 10.1016/j.renene.2011.08.046.

[4] V. A. Koehuan, Sugiyono, and S. Kamal, “Investigation of counter-rotating wind turbine performance using computational fluid dynamics simulation,” IOP Conf. Ser. Mater. Sci. Eng., vol. 267, no. 1, pp. 0–9, 2017, doi: 10.1088/1757-899X/267/1/012034.

[5] H. A. Abdel Karim, A. R. El-Baz, N. A. Aziz Mahmoud, and A. M. Hamed, “Numerical analysis on the performance of Dual Rotor wind turbine,” Int. J. Sci. Res. Manag., vol. 8, no. 03, pp. 352–368, 2020, doi: 10.18535/ijsrm/v8i03.ec02.

[6] S. Lee, E. Son, and S. Lee, “Velocity interference in the rear rotor of a counter-rotating wind turbine,” Renew. Energy, vol. 54, pp. 235–240, 2013, doi: 10.1016/j.renene.2012.08.003.

[7] B. Hwang, S. Lee, and S. Lee, “Optimization of a counter-rotating wind turbine using the blade element and momentum theory,” J. Renew. Sustain. Energy, vol. 5, no. 5, 2013, doi: 10.1063/1.4826940.

[8] Z. Wang, A. Ozbay, W. Tian, and H. Hu, “An experimental study on the aerodynamic performances and wake characteristics of an innovative dual-rotor wind turbine,” Energy, vol. 147, pp. 94–109, 2018, doi: 10.1016/j.energy.2018.01.020.

[9] W. Yuan, W. Tian, A. Ozbay, and H. Hu, “An experimental study on the effects of relative rotation direction on the wake interferences among tandem wind turbines,” Sci. China Physics, Mech. Astron., vol. 57, no. 5, pp. 935–949, 2014, doi: 10.1007/s11433-014-5429-x.

[10] A. D. Hoang and C.-J. Yang, “Design and Performance Evaluation of a 10kW Scale Counter-Rotating Wind Turbine Rotor,” J. Korean Soc. Mar. Environ. Saf., vol. 20, no. 1, pp. 104–112, 2014, doi: 10.7837/kosomes.2014.20.1.104.

[11] P.-Å. Krogstad and J. A. Lund, “An experimental and numerical study of the performance of a model turbine,” Wind Energy, vol. 15, no. 3, pp. 443–457, Apr. 2012, doi: 10.1002/we.482.

[12] M. H. Lee, Y. C. Shiah, and C. J. Bai, “Experiments and numerical simulations of the rotor-blade performance for a small-scale horizontal axis wind turbine,” J. Wind Eng. Ind. Aerodyn., vol. 149, pp. 17–29, 2016, doi: 10.1016/j.jweia.2015.12.002.

[13] J. O. Mo and Y. H. Lee, “CFD Investigation on the aerodynamic characteristics of a small-sized wind turbine of NREL PHASE VI operating with a stall-regulated method,” J. Mech. Sci. Technol., vol. 26, no. 1, pp. 81–92, 2012, doi: 10.1007/s12206-011-1014-7.