On the tribo-dynamic behaviors during start-up of water lubricated bearing considering imperfect journal

The novelty of this paper is to explore the role of the imperfect journal, including the amplitude and waviness of journal error, on the tribo-dynamic behaviors of the water-lubricated bearing during start-up. To characterize the lubrication performance more practically, the elastic-plastic asperity contact behavior during start-up is considered in the transient hydrodynamic modeling process. We perform a comparative analysis with the published experimental results to verify the correctness of the present model. According to the numerical model, the impacts of the imperfect journal on the tribo-dynamic behavior of the water-lubricated bearing during start-up within a wide range of surface roughness and radial clearance are analyzed. Numerical results demonstrate that the role of the imperfect journal on the tribo-dynamic behavior of the water-lubricated bearing during start-up should be emphasized. Also, the negative effect of the journal shape error on the tribo-dynamic behavior can be identified at a relatively high journal waviness order. When the relative journal error amplitude Δr is less than 1% of radial bearing clearance, the journal shape error slightly affects the tribo-dynamic performance during start-up. However, when the relative journal error amplitude Δr is in the range of 2–9% of radial bearing clearance, a reasonable journal error can improve the tribo-dynamic performance of the water-lubricated bearing during start-up. •A tribo-dynamic model for the water-lubricated bearing during start-up considering imperfect journal is developed.•The role of s on the tribo-dynamic behavior of the water-lubricated bearing during start-up is evaluated.•It is shows that the journal shape errors are dependent on the bearing design parameters.