Influence of Axial Microvibration on the Transient Hydrodynamic Lubrication Performance of Misaligned Journal–Thrust Microgrooved Coupled Bearings under Water Lubrication

Abstract

The purpose of this study is to explore the transient hydrodynamic coupling mechanism for misaligned journal–thrust microgrooved coupled bearings (referred to as coupled bearings) considering the axial microvibration under water lubrication. In the present model, it is assumed that the misaligned coupled bearing performs a sinusoidal reciprocating micromotion along the axial direction. Based on the developed numerical model, the effects of the working conditions, including the frequency and amplitude of the microvibration, misalignment angle, journal bearing radial clearance, and thrust bearing geometric clearance, on the transient hydrodynamic performance of the coupled bearing are studied. The simulation results indicate that the axial microvibration generates a periodic fluctuation in the load capacity for both the journal and thrust bearings, and the load fluctuation of the journal bearing is generated from the transient hydrodynamics of the thrust bearing. In addition, the negative misalignment mode is beneficial to improve the load capacity of the coupled bearing. Parametric studies demonstrate that although the decreasing microvibration frequency weakens the load capacity of the coupled bearing, it decreases the hydrodynamic load fluctuation. They also reveal that the increasing misalignment angle leads to an increase in the load fluctuation, and it also improves the load capacity.