Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지
DOI QR코드

DOI QR Code

Visualization of Flow Field of Weis-Fogh Type Water Turbine Using the PIV

PIV를 이용한 Weis-Fogh형 수차의 유동장 가시화

  • Ro, Ki Deok (Dept. of Mechanical System Engineering, Gyeongsang Nat'l Univ.)
  • 노기덕 (경상대학교 기계시스템공학과)
  • Received : 2016.08.14
  • Accepted : 2016.12.06
  • Published : 2017.03.01
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, the visualization of the unsteady flow field of a Weis-Fogh-type water turbine was investigated using particle-image velocimetry. The visualization experiments were performed in a parameter range that provided relatively high-efficiency wing conditions, that is, at a wing opening angle ${\alpha}=40^{\circ}$ and at a velocity ratio of the uniform flow to the moving wing U/V = 1.5~2.5. The flow fields at the opening, translational, and closing stages were investigated for each experimental parameter. In the opening stage, the fluid was drawn in between the wing and wall at a velocity that increased with an increase in the opening angle and velocity ratio. In the translational stage, the fluid on the pressure face of the wing moved in the direction of the wing motion, and the boundary layer at the back face of the wing was the thinnest and had a velocity ratio of 2.0. In the closing stage, the fluid between the wing and wall was jetted at a velocity that increased as the opening angle decreased; however, the velocity was independent of the velocity ratio.

본 연구는 Weis-Fogh형 수차모델의 비정상 유동장을 PIV를 이용해 가시화한 것이다. 실험은 비교적 효율이 높은 날개의 열림각 ${\alpha}=40^{\circ}$ 및 날개의 이동 속도에 대한 일정류의 속도비 U/V=1.5~2.5 범위 내에서 진행했다. 유동장은 각 실험 파라메터에 대해 열리는 과정, 병진운동의 과정 및 닫히는 과정으로 나누어 고찰되었으며, 그 결과를 요약하면 다음과 같다. 열리는 과정에서는 날개와 벽 사이에 유체가 흡입되며, 그 유입속도는 열림각이 클수록, 속도비가 클수록 증가했다. 병진운동의 과정에서 날개 압력면의 유체는 날개의 이동방향으로 움직였으며, 배면에서의 경계층의 두께는 속도비 2.0일 때 가장 작았다. 닫히는 과정에서는 날개와 벽 사이에서 유체가 분출되며, 그 분출속도는 열림각이 작을수록 증가했지만, 속도비와는 관계가 없었다.

Keywords

References

  1. Weis-Fogh, T., 1973, "Quick Estimates of Flight Fitness in Hovering Animals, Including Novel Mechanism for Lift Production," Journal of Experimental Biology, Vol. 59, pp. 169-230.
  2. Lighthill, M. J., 1973, "On the Weis-Fogh Mechanism of Lift Generation," Journal of Fluid Mechanics, Vol. 60, Part1, pp. 1-17. https://doi.org/10.1017/S0022112073000017
  3. Maxworthy, T., 1979, "Experiments on the Weis-Fogh Mechanism of Lift Generation by Insects in Hovering Flight. Part 1. Dynamics of the 'Fling'," Journal of Fluid Mechanics, Vol. 93, pp. 47-63. https://doi.org/10.1017/S0022112079001774
  4. Edwards, R. H. and Cheng, H. K., 1982, "The Separation Vortex in the Weis-Fogh Circulation- Generation Mechanism," Journal of Fluid Mechanics, Vol. 120, pp. 463-473. https://doi.org/10.1017/S0022112082002857
  5. Spedding, G. R. and Maxworthy, T., 1986, "The Generation of Circulation and Lift in a Rigid Two-Dimensional Fling," Journal of Fluid Mechanics, Vol. 165, pp. 247-272. https://doi.org/10.1017/S0022112086003087
  6. Ro, K. D. and Tsutahara, M., 1997, "Numerical Analysis of Unsteady Flow in the Weis-Fogh Mechanism by the 3D Discrete Vortex Method with GRAPE3A," Journal of Fluids Engineering, Vol. 119 pp. 96-102. https://doi.org/10.1115/1.2819125
  7. Zhang, S. S., Wu, X. H. and Wang, X. F., 1999, "Research and Progress of Weis-Fogh Mechanism Hydrodynamics," Journal of Hydrodynamics, Vol. 3. pp. 55-60.
  8. Maxworthy, T., 2007, "The Formation and Maintenance of a Leading Edge Vortex during the Forward Motion of Animal Wing," Journal of Fluid Mechanics, Vol. 587, pp. 471-475.
  9. Kolomenskiy, D., Moffatt, H.K., Farge, M. and Schneider, K., 2011, "The Lighthill-weis-fogh Clapfling-sweep Mechanism Revisited," Journal of Fluid Mechanics, Vol. 676, pp.573-606.
  10. Furber, S. B. and Ffowcs Williams, J. E., 1979, "Is the Weis-Fogh Principle Exploitable in Turbomachinary?," Journal of Fluid Mechanics, Vol. 94, Part 3, pp. 519-540. https://doi.org/10.1017/S0022112079001166
  11. Tsutahara, M. and Kimura, T., 1987, "An Application of the Weis-Fogh Mechanism to Ship Propulsion," Journal of Fluids Engineering, Vol. 109, pp. 107-113. https://doi.org/10.1115/1.3242629
  12. Tsutahara, M. and Kimura, T., 1987, "A Pilot Pump using the Weis-Fogh Mechanism and its Characteristics," Trans. of the JSME(B), Vol. 54, No. 498, pp. 393-397.
  13. Tsutahara, M. and Kimura, T., 1994, "Study of a Fan Using the Weis-Fogh Mechanism(An Experimental Fan and Its Characteristics)," Trans. of the JSME(B), Vol. 60, No. 571, pp. 910-915. https://doi.org/10.1299/kikaib.60.910
  14. Ro, K. D., Zhu, B. S. and Kang, H. K., 2006, "Numerical Analysis of Unsteady Viscous Flow Through a Weis-Fogh Type Ship Propulsion Mechanism Using the Advanced Vortex Method," Journal of Fluids Engineering, Vol. 128, pp. 481-487. https://doi.org/10.1115/1.2174059
  15. Ro, K.-D. and Seok, J.-Y. 2010, "Sailing Characteristics of a Model Ship of Weis-Fogh Type," Trans. Korean Soc. Mech. Eng. B, Vol. 34, No. 1, pp. 45-52. https://doi.org/10.3795/KSME-B.2010.34.1.45
  16. Ro, K.-D. 2010, "Performance Improvement of Weis-Fogh Type Ship's Propulsion Mechanism Using a Wing Restrained by an Elastic Spring," Journal of Fluids Engineering, Vol. 132, No. 4, pp. 041101-1-041101-6. https://doi.org/10.1115/1.4001155
  17. Ro, K.-D. 2012, "Numerical Calculation of Unsteady Flow Fields: Feasibility of Applying the Weis-Fogh Mechanism to Water Turbines," Journal of Fluids Engineering, Vol. 135, No. 10, pp. 101103-1-101103-6. https://doi.org/10.1115/1.4024956
  18. Ro, K.-D., 2014, "Calculation of Hydrodynamic Characteristics of Weis-Fogh Type Water Turbine Using the Advanced Vortex Method," Trans. of the KSME(B), Vol. 38, No.3, pp. 203-210.
  19. Ro, K.-D., 2014, "Experiments on Hydrodynamic Performance of Weis-fogh-type Water Turbine," Trans. of the CSME, Vol. 38, No. 3, pp. 405-415.
  20. Ro, K.-D., "Hydrodynamic Calculation of Rotating Weis-Fogh Type Water Turbine with the Advanced Vortex Method," Trans. of the CSME, Vol. 39, No. 2, pp. 337-355.