Performance of high-speed hydrodynamic sliding bearings with lubricating oils combining laminar and turbulent flows

Abstract

High-speed hydrodynamic sliding bearings use lubricating oil that can have laminar and turbulent flow states, yet turbulent states remain relatively unstudied. This study combines theoretical analysis, numerical modeling, and experiments to analyze lubrication fluids in such bearings. It considers Reynolds equations, energy equations, and temperature-viscosity relationships under laminar and turbulent flows. The governing equations are solved by the finite difference method. Two-dimensional distributions of Reynolds number, pressure, and temperature in the bearing film, as well as the lubrication characteristics like bearing capacity and frictional force under working conditions, are analyzed. Single and mixed flow states are compared, which demonstrates the coexistence states of laminar and turbulent flows in an oil film under specific working conditions. Oil film flow distributions differ significantly according to rotational speed and eccentric conditions. Flow changes under high eccentricity are complex. The characteristics of oil films in a single flow state deviate significantly from those in mixed flow. Changes in flow state and heat should not be ignored during analysis of the lubrication performance of high-speed bearings.