Tribology and Lubricants

Korean Tribology Society (한국트라이볼로지학회)
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Predictions of Load Support Performance of a Pressurized Gas Foil Thrust Bearing with Sloped and Stepped Recesses

경사형과 계단형 리세스를 갖는 가압형 가스 포일 스러스트 베어링의 하중지지 성능 예측

  • Nam Kyu Kim (Graduate School, Dept. of Mechanical Systems Engineering, Kookmin University) ;
  • YongBum Kwon (Graduate School, Dept. of Mechanical Systems Engineering, Kookmin University) ;
  • Chan Sol Park (Graduate School, Dept. of Mechanical Systems Engineering, Kookmin University) ;
  • Tea Ho Kim (School of Mechanical Engineering, Kookmin University)
  • 김남규 (국민대학교 대학원 기계시스템공학과) ;
  • 권용범 (국민대학교 대학원 기계시스템공학과) ;
  • 박찬솔 (국민대학교 대학원 기계시스템공학과) ;
  • 김태호 (국민대학교 기계공학부)
  • Received : 2024.09.24
  • Accepted : 2024.10.24
  • Published : 2024.10.31
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Abstract

Gas foil thrust bearings (GFTBs) support axial loads in oil-free, high speed rotating machinery using gas as a lubricant. However, under low-speed and high-load conditions, such a bearing experiences friction, leading to wear and a reduced lifespan. Therefore, a pressurized GFTB (PGFTB) that combines hydrostatic and hydrodynamic lubrication by supplying pressurized gas through the supply hole of the top foil has been developed, and various studies have been conducted. In this study, we develop mathematical models of PGFTBs with sloped and stepped recesses and predict its load support performance. The PGFTB maintains a minimum film thickness of approximately 20 ㎛ at rest (0 rpm), regardless of the type of recess, indicating a sufficient hydrostatic pressure to lift the runner at a low rotor speed. Furthermore, the minimum film thickness increases slightly as the numbers of feed holes in the in- and outward radial directions relative to the centerline of the PGFTB pad increase. These findings highlight the importance of supply hole placement in enhancing load support performance. As the rotor speed increases, the minimum film thickness increases rapidly, regardless of the number of supply holes, and without pressurization, sufficient hydrodynamic pressure is generated to lift the runner upon exceeding a certain rotor speed. When comparing the sloped and stepped recesses, the PGFTB with the sloped groove exhibits a superior overall load support performance.

Keywords

Acknowledgement

본 연구는 2024년도 산업통상자원부의 재원으로 한국에너지기술평가원(KETEP)의 지원을 받아 수행한 "AI/ICT 기반 가변형 유체기기 설계, 상태진단을 위한 기반 플랫폼 기술 및 운영관리 시스템 개발" 연구과제(2021202080026D)의 일환으로 수행되었으며, 이에 관계자 여러분께 감사드립니다.

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