# 표면이 마모된 틸팅 패드 저널베어링의 열윤활 해석 및 온도 측정

• Lee, Donghyun (Dept. of System Dynamics, Korea Institute of Machinery and Material) ;
• Sun, Kyungho (Dept. of System Dynamics, Korea Institute of Machinery and Material) ;
• Kim, Byungock (Dept. of System Dynamics, Korea Institute of Machinery and Material) ;
• Kang, Donghyuk (Dept. of System Dynamics, Korea Institute of Machinery and Material)
• 이동현 (한국기계연구원 시스템다이나믹스 연구실) ;
• 선경호 (한국기계연구원 시스템다이나믹스 연구실) ;
• 김병옥 (한국기계연구원 시스템다이나믹스 연구실) ;
• 강동혁 (한국기계연구원 시스템다이나믹스 연구실)
• Accepted : 2017.07.31
• Published : 2017.08.31

#### Abstract

With the increase in adoption of tilting pad journal bearings (TPJBs), various failure mechanisms related to TPJBs have been reported, of which pad wear is a frequently reported one. Pad wear causes change in geometry of the bearing, which can sometimes result in the failure of the entire system. The objective of this research is to investigate the influence of pad wear on the pad temperature, which is one of the widely used condition monitoring methods for TPJBs. For the theoretical investigation, thermohydrodynamic (THD) analysis was conducted by solving the generalized Reynolds equation and the 3D energy equation. The results of the analysis show that the temperature of the loaded pad increases while that of the unloaded pad decreases, when there is wear on the loaded pads. In addition, the minimum film thickness decreases with an increase in the wear depth. A validation test was conducted with a test rig, which mimics the axial turbine when a test rotor is supported by two TPJBs. The test bearing consists of five pads with a diameter of 60 mm, and a resistance temperature detector (RTD) is installed in the pad for temperature monitoring. The test was performed by replacing the two loaded pads with the worn pad. The test result for the TPJB with wear depth of $30{\mu}m$ show that the temperatures of the loaded pads are $8^{\circ}C$ higher and that of the unloaded pad is $2.5^{\circ}C$ lower than that of the normal TPJB. In addition, the predicted pad temperature shows good agreement with the measured pad temperatures.

#### Acknowledgement

Supported by : 한국 연구 재단

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