Journal of the Korean Society for Aeronautical & Space Sciences (한국항공우주학회지)

The Korean Society for Aeronautical and Space Sciences (한국항공우주학회)
권호 표지
DOI QR코드

DOI QR Code

Comparison of Aerodynamic Loads for Horizontal Axis Wind Turbine (II): with and without Vertical Wind Shear Effect

수평축 풍력터빈의 공력 하중 비교 (II): 수직 전단흐름 효과의 유·무

  • Kim, Jin (Power & Industrial Systems Performance Group, Hyosung) ;
  • Kang, Seung-Hee (Department of Aerospace Engineering, Chonbuk National University) ;
  • Ryu, Ki-Wahn (Department of Aerospace Engineering, Chonbuk National University)
  • Received : 2016.02.18
  • Accepted : 2016.04.27
  • Published : 2016.05.01
Download PDF
⟨ Previous Next ⟩

Abstract

The large scale wind turbine blades usually experience periodic change of inflow speed due to blade rotation inside the ground shear flow region. Because of the vertical wind shear, the inflow velocity in the boundary layer region is maximum at uppermost position and minimum at lowermost position. These spatial distribution of wind speeds can lead to the periodic oscillation of the 6-component loads at hub and low speed shaft of the wind turbine rotor. In this study we compare the aerodynamic loads between two inflow conditions, i.e, uniform flow (no vertical wind shear effect) and normal wind profile. From the computed results all of the relative errors for oscillating amplitudes increased due to the ground shear flow effect. Especially bending moment and thrust at hub, and bending moments at LSS increased enormously. It turns out that the aerodynamic analysis including the ground shear flow effect must be considered for fatigue analysis.

대형 풍력터빈은 지상 전단 흐름 내에서 회전하면서 주기적인 유입속도의 변동 조건 하에 운용된다. 수직 전단흐름에 의해서 경계층 내의 유입 속도는 최고점에서 속도가 최대가 되고 최저점에서 속도가 최소가 된다. 이러한 공간적인 풍속 분포는 풍력터빈 로터의 허브와 저속회전축에서 6분력 하중에 대한 주기적인 진동을 야기한다. 본 연구에서는 수직 전단 흐름 효과를 무시한 균일 흐름장과 지상 전단 흐름효과를 고려한 두 가지 경우에 대한 공력 하중을 비교분석하였다. 계산 결과로부터 허브에서의 추력과 굽힘모멘트, LSS의 굽힘모멘트가 크게 변동하는 결과를 보여주었다. 따라서 지상 전단흐름 효과를 반영한 공력 해석이 피로 해석을 위해서 반드시 필요함을 확인하였다.

Keywords

References

  1. Burton, T., Sharpe, D., Jenkins, N., andBossanyi, E., Wind energy handbook, 2ndedition, John Wiley & Sons, 2011.
  2. Bailey, B. H., "Predicting vertical wind profiles as a function of time of the day and surface wind speed," Proceedings of an International Colloquium on Wind Energy, BWEA, Brighton, UK, 1981.
  3. IEC-61400-1, Wind Turbine Generator Systems, Part 1: Safety Requirements. International Electrotechnical Commission, Geneva, Swiss, 2005.
  4. KIm, D. H., Lee, J. H., Tran, T. T., Kwak, Y. S., and Song, J. S., "Extreme Design Load Case Analyses of a 5 MW Offshore Wind Turbine Using Unsteady Computational Fluid Dynamics," Journal of Wind Energy, Vol. 5, No. 1, 2014, pp. 22-32.
  5. Ryu, Ki-Wahn, "Optimal Aerodynamic Design and Performance Analysis for Pitch-Controlled HAWT," Journal of the Korean Society for Aeronautical and Space Sciences, Vol. 35, No. 10, 2007, pp. 891-898. https://doi.org/10.5139/JKSAS.2007.35.10.891
  6. Viterna, L. A., and Corrigan, R. D., "Fixed pitch rotor performance of large horizontal axis wind turbines," Proceedings, Workshop on Large Horizontal Axis Wind Turbine, NASA, P-2203, DOE Publication. CONF-810752, Cleveland, OH: NASA Lewis Research Center, 1981, pp. 69-85.
  7. Himmelskamp, H., Profile investigations on a rotating airscrew, Ph.D. Thesis, Gottingen University. Germany, 1945.
  8. Du, Z. and Selig, M. S., "A 3-D stalldelay model for horizontal axis wind turbineperformance prediction," Proc. 1998 ASME Wind Energy Symposium, 36th AIAA Aerospace Science Meeting, AIAA 1998-0021, 1998.
  9. Betz, A., Schraubenpropeller mit geringstem energieverlust, Gottinger Nachr., Germany, 1919.
  10. Buhl, M. L., Jr., A new empirical relationship between thrust coefficient and induction factor for the turbulent windmill state, NREL/TP-500-36834, Golden, CO. NREL, September, 2004.
  11. Hansen, M. H., Gaunaa, M., Aagaard Madsen, H., "A Beddoes-Leishman type dynamic stall model in state-space and indicial formulation," RisO-R-1354, Roskilde, Denmark, 2004.
  12. Hsu, S. A., "Determining the power-law wind-profile exponent under near neutral stability conditions at sea," Journal of Applied Meteorology, 1994, pp. 757-765.
  13. Jonkman, J. M., and Buhl, M. L., Jr., FAST User's Guide, NREL/EL-500-29798, NREL, March, 2004.
  14. Moriarty, P. J., Hansen, A. C., "AeroDyn Theory Manual," NREL/TP-500-36881, January, 2005.

Cited by

  1. A Comparative Study on Aerodynamic Validation in Design Process of an Airfoil for Megawatt-Class Wind Turbine vol.44, pp.11, 2016, https://doi.org/10.5139/JKSAS.2016.44.11.933
  2. An Investigation on Thrust Properties under Wind Shear for an On-Shore 2 MW Wind Turbine vol.19, pp.6, 2016, https://doi.org/10.5293/kfma.2016.19.6.014