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

The Korean Society of Mechanical Engineers (대한기계학회)
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Damage Analysis for Last-Stage Blade of Low-Pressure Turbine

저압터빈 최종단 블레이드 손상해석

  • Song, Gee Wook (Korea Electric Power Corporation, Research Institute) ;
  • Choi, Woo Sung (Korea Electric Power Corporation, Research Institute) ;
  • Kim, Wanjae (Korea Electric Power Corporation, Research Institute) ;
  • Jung, Nam Gun (Korea Electric Power Corporation, Research Institute)
  • 송기욱 (한국전력공사 전력연구원) ;
  • 최우성 (한국전력공사 전력연구원) ;
  • 김완재 (한국전력공사 전력연구원) ;
  • 정남근 (한국전력공사 전력연구원)
  • Received : 2012.06.18
  • Accepted : 2013.10.03
  • Published : 2013.12.01
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Abstract

A steam turbine blade is one of the core parts in a power plant. It transforms steam energy into mechanical energy. It is installed on the rim of a rotor disk. Many failure cases have been reported at the final stage blades of a low-pressure (LP) turbine that is cyclically loaded by centrifugal force because of the repeated startups of the turbine. Therefore, to ensure the safety of an LP steam turbine blade, it is necessary to investigate the fatigue strength and life. In this study, the low cycle fatigue life of an LP steam turbine blade is evaluated based on actual damage analysis. To determine the crack initiation life of the final stage of a steam turbine, Neuber's rule is applied to elastic stresses by the finite element method to calculate the true strain amplitude. It is observed that the expected life and actual number of starts/stops of the blade were well matched.

증기터빈의 터빈 블레이드는 발전소 핵심설비 중 하나로, 로터의 디스크에 결합되어 회전함으로 써 증기 에너지를 기계적 에너지로 변환시켜주는 역할을 하고 있다. 최근 터빈의 잦은 기동정지로 인해 블레이드 회전에 따른 원심하중이 반복적 작용하고 이에 따른 저압 증기터빈 최종단 블레이드의 손상이 자주 보고되고 있다. 본 논문에서는 터빈 블레이드에 발생되는 손상을 분석하여 블레이드에 발생되는 저주기 피로수명을 평가하였다. 증기터빈 최종단 블레이드의 균열발생 수명을 결정하기 위해 유한요소법으로 계산한 탄성응력에 Neuber's rule을 적용하여 진변형율 진폭을 계산하였으며, 예측된 수명과 블레이드 실제 기동정지횟수가 잘 일치됨을 보였다.

Keywords

References

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Cited by

  1. Fatigue Damage Analysis of a Low-Pressure Turbine Blade vol.39, pp.7, 2015, https://doi.org/10.3795/KSME-A.2015.39.7.713
  2. Study for Fracture in the Last Stage Blade of a Low Pressure Turbine vol.40, pp.4, 2016, https://doi.org/10.3795/KSME-A.2016.40.4.423