Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

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

DOI QR Code

Numerical Study of Aerodynamics of Turbine Rotor with Leading Edge Modification Near Hub

허브 측 선단 수정에 따른 터빈 로터의 공력 특성에 대한 수치적 연구

  • Received : 2011.12.28
  • Accepted : 2013.07.08
  • Published : 2013.08.01
Download PDF
⟨ Previous Next ⟩

Abstract

This study aims to analyze the aerodynamics when the geometry of the turbine rotor is modified. The turbine used in this study is a small engine used in the APU of a helicopter. It is difficult to improve the performance of small engines owing to the structural weakness of the blade tip. Therefore, the improvement of the hub geometry is investigated in many ways. The working fluid of a turbine is a high-temperature and high-pressure gas. The heat transfer rate of the turbine surface should be considered to avoid the destruction of blade owing to the heat load. The SST turbulence model gives an excellent prediction of the aerodynamic behavior and heat transfer characteristics when the numerical simulations are compared with the experimental results. In conclusion, the aerodynamic efficiency is improved when a bulbous design is applied to the leading edge near the hub. The endwall loss is reduced by 15%.

이 논문은 터빈 로터의 형상변화에 따른 공력 특성에 대하여 분석하였다. 본 논문의 터빈은 헬리콥터의 보조동력 장치로 사용되는 소형엔진이다. 소형엔진은 팁 형상의 구조적 취약성 때문에 성능을 향상시키기 어렵다. 그러므로, 터빈의 허브를 개선하는 것이 여러 가지 측면에서 유리하다. 터빈의 작동유체는 고온 고압의 가스이다. 터빈표면의 열전달률이 고려되었을 때, 열부하에 의한 블레이드의 손상을 줄이기 위해서는 블레이드 표면의 열전달률 분포를 고찰하여야 한다. 수치모사 결과를 검증용 실험값과 비교하였을 때, SST난류모델은 공력 특성을 잘 반영하고 열전달 예측성능도 우수하였다. 결론적으로, 허브측 선단에서 구륜설계(bulbous design)를 적용하였을 때 공력효율이 향상되었고, 전체 공력 손실 중 끝벽 손실은 15% 감소되었다.

Keywords

References

  1. Shama, O.P. and Butler, T.L., 1987. "Predictions of Endwall Losses and Secondary Flows in Axial Flow Turbine Cadcades." ASME Journal of Turbomachinery, Vol. 109, pp. 229-236. https://doi.org/10.1115/1.3262089
  2. Azad, GM S., Han, J. C. and Boyle, R., 2000, "Heat Transfer and Pressure Distributions on a Gas Turbine Blade Tip," Trans. of ASME J. of Turbomachinery, 122, pp. 717-724. https://doi.org/10.1115/1.1308567
  3. Azad, GM S., Han, J. C. and Boyle, R., 2000, "Heat Transfer and Pressure Distributions on the Squealer Tip of a Gas Turbine Blade," Trans. of ASME J. of Turbomachinery, 122, pp. 725-732. https://doi.org/10.1115/1.1311284
  4. Acharya, S., Yang, H., Prakash, C. and Bunker, R., 2003, "Numerical Study of Flow and Heat Transfer in a Blade Tip with Different Leakage Reduction Strategies," ASME paper, No. GT2003-38617.
  5. Yang, H., Chem, H. C. and Han, J. C., 2005, "Flow and Heat Transfer Prediction on Turbine Blade and Shroud in a Low Speed Annular Cascade(II)," Trans. Korean Soc. Mech. Eng. B, Vol. 29, pp. 495-503.
  6. Kwak, J. S., 2006, "Effect of Blade Tip Geometry on Heat Transfer Coefficients on Gas Turbine Blade Tips and Near Tip Regions," Trans. Korean Soc. Mech. Eng. B, Vol. 30, No. 4, pp. 328-336. https://doi.org/10.3795/KSME-B.2006.30.4.328
  7. Dey, D. and Camci, C., 2004, "Tip Desensitization of an Axial Turbine Rotor Using Tip Platform Extensions," VKI Lecture Series, 2004-02.
  8. Cengiz C. and Akamol S., 2008, "Pressure Side Tip Platform Extensions for Tip Leakage Control in Axial Turbines," Progress in Computational Fluid Dynamics, Vol. , Nos.
  9. Stephens. J., Tomas C. and Morris. S., 2007, "Turbine Blade Tip Leakage Flow Control: Thick/Thin Blade Effects" 45th AIAA Aerospace Sciences Meeting and Exhibit.
  10. Sauer, H., Muller, R. and Vogeler, K., 2001, "Reduction of Secondary Flow Losses in Turbine Cascadesby Leading Edge Modifications at the Endwall," Journal of Turbomachinery, Vol. 123, Issue 2, pp. 207-213. https://doi.org/10.1115/1.1354142
  11. Moustapha, S. H. and Williamson, R. G., 1986, "Effect of Two Endwall Contours on the Performance of an Annular Nozzle Cascade," AIAA Journal, Vol. 84, No. 9.
  12. Morris, A. W. and Hoare, R. G., 1975, "Secondary Loss Measurements in a Cascade of Turbine Blades With Meridional Wall Profiling," ASME Paper, No. 75-WA/GT-13 137-145.
  13. Han, S. and Goldstein R. J., 2006, Influence of Blade Leading Edge Geometry on Turbine Endwall Heat(Mass) Transfer, Journal of Fluids Engineering, Vol. 129.
  14. Han, S. and Goldstein R. J., 2002, Influence of Blade Leading Edge Geometry on Turbine Endwall Heat(Mass) Transfer, Proceedings of ASME Paper No. GT2002-30353.
  15. Mahmood, G. I. and Acharya, S., 2007, "Experimental Investigation of Secondary Flow Structure in a Blade Passage With and Without Leading Edge Fillets," Journal of Fluids Engineering, Vol. 1291.1.
  16. Barth, T. J. and Jesperson, D. C., 1989, "The Design and Application of Upwind Schemes on Unstructured Meshes," AIAA Paper 89-0366.