Study on Static Thermo-hydrodynamic Lubrication of Floating Ring Bearing

doi:10.3901/JME.2017.23.108

Abstract

Abstract: The ring speed ratio largely determines the steady state and dynamic response of a floating ring bearing (FRB). Extensive experiments demonstrate FRB speed ratios have a strong nonlinear relationship with journal rotative speed, but theoretical predictions show significant discrepancies with test data. Aiming at solving this problem, a thermal-hydrodynamic model is established to investigate the lubrication performance of FRB. The state and dynamic performance of FRB under several typical operational conditions are calculated. The relationship between speed ratio and journal rotative speed is investigated under isothermal, conducive and adiabatic conditions. The influence of ring material on the speed ratio is also addressed. Furthermore, the fitness conditions of the classical analytical formula of speed ratio is discussed. The main conclusions are as follows:the isothermal model overestimate the speed ratio significantly under a wide range of rotative speed, whereas the results of conducive thermal model shows a good agreement with existing experiment data. Both the theoretical and experimental results show that the speed ratio increase sharply at low speed, then decrease gradually with further increasing journal rotative speed. The ring speed ratios decrease under moderate and high shaft speed is mainly due to the difference of the lubricant viscosity between inner and outer film and the variation in film clearances owing to thermal growth of the components. Hence, the thermal effect is mandatory for reliable FRB design.

Key words: floating ring bearing, ring speed ratio, thermal effect, thermo-hydrodynamic (THD)

CLC Number:

TH133

PEI Shiyuan, XU Hua, SHI Fanghui. Study on Static Thermo-hydrodynamic Lubrication of Floating Ring Bearing[J]. Journal of Mechanical Engineering, 2017, 53(23): 108-115.

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