Tribology and Lubricants

Korean Tribology Society (한국트라이볼로지학회)
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Thermal Analysis and Temperature Measurement of Tilting Pad Bearings Supporting a Power Turbine for the Supercritical CO2 Cycle Application

초임계 CO2 발전용 파워터빈을 지지하는 틸팅패드 베어링의 열윤활 해석 및 패드 온도 측정

  • Lee, Donghyun (Dept. of System Dynamics, Korea Institute of Machinery and Material) ;
  • Kim, Byungok (Dept. of System Dynamics, Korea Institute of Machinery and Material) ;
  • Lim, Hyungsoo (Dept. of Energy Conversion System, Korea Institute of Machinery and Materials)
  • 이동현 (한국기계연구원 시스템다이나믹스 연구실) ;
  • 김병옥 (한국기계연구원 시스템다이나믹스 연구실) ;
  • 임형수 (한국기계연구원 에너지변환기계 연구실)
  • Received : 2018.02.25
  • Accepted : 2018.03.26
  • Published : 2018.04.30
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Abstract

This paper presents the thermohydrodynamic analysis of tilting journal pad bearings supporting a power turbine rotor applied to a 250 kW super-critical $CO_2$ cycle. In the analysis, the generalized Reynolds equation and 3D energy equation are solved to predict oil film temperature and the 3D heat conduction equation is solved for pad temperature. The power turbine rotor is supported by two tilting pad bearings consisting of five pads with an oil supply block between the pads. Copper backing pads with higher thermal conductivity compared to steel backing pads are adopted to improve thermal management. The predicted maximum pad temperature is around $55^{\circ}C$ which is approximately $15^{\circ}C$ higher than oil supply temperature. In addition, the predicted minimum film thickness is 50 mm at a rotating speed of 5,000 rpm. These results indicate that there is no issue in the thermal behavior of the bearing. An operation test is performed with a power turbine module consisting of a power turbine, a reduction gear and a generator. Thermocouples are installed at the 75% position from the leading edge of the pad to monitor pad temperature. The power turbine uses compressed air at a temperature of $250^{\circ}C$ in its operation. The steady state pad temperatures measured in the test show good agreement with the predicted temperatures.

Keywords

References

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