Research on the Start-up Characteristics of Worn Journal Bearings Lubricated by Non-Newtonian Fluid

doi:10.3901/JME.260831

Abstract

Abstract: To accurately analyze the start-up characteristics of journal bearings under the combined influence of lubricant non-Newtonian effect and bearing surface wear defects, the lubrication equation under the combined impact of surface roughness and non-Newtonian effect, namely the transient modified average Reynolds equation, is derived using the average flow method. The lubrication model for bearing start-up characteristic analysis is formed by combining the bearing film thickness equation (established by applying the Dufrane model that considers the bearing surface's wear defects) and the dynamic equation of the journal center motion. The finite difference method and Newton's method are used to solve the transient modified average Reynolds equation and the journal center motion equation, respectively, and the starting characteristics of the bearing under different power-law exponents and different relative worn defects are analyzed. The results show that compared with bearings without worn defects, bearings with worn defects have larger minimum film thickness and maximum average film pressure peak and smaller maximum contact pressure peak, contact time, and lift-off speed. The change in the power-law exponent has no obvious effect on the maximum contact pressure, contact time, and lift-off speed of the bearing's starting. In addition, the proposed transient modified average Reynolds equation is not only applicable to journal bearings, but also to non-Newtonian fluid lubricated bearings such as thrust bearings and elliptical journal bearings.

Key words: journal bearing, non-Newtonian effect, worn defect, start-up

CLC Number:

TH117

ZHU Shaoyu, ZHANG Xiangjun, SUN Jun, WANG Dagang. Research on the Start-up Characteristics of Worn Journal Bearings Lubricated by Non-Newtonian Fluid[J]. Journal of Mechanical Engineering, 2026, 62(15): 484-496.

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