Study on the influence of critical shear stress on wall slip of spiral oil wedge journal bearing

Abstract

With the application of sleeve bearing in high speed, super-high speed and narrow-gap conditions, and the emergence of non-metallic bearing materials, the conventional no-slip boundary condition can be broken down. Critical shear stress is a main parameter in the numerical computation of wall slip. The four modified Reynolds equations for the two-dimensional spiral oil wedge sleeve bearing is established based on the critical shear stress model, in which the circumferential and axial wall slip of the sleeve and axial surface are considered. The shear stress angle is used to compute the circumferential and axial shear stress component and slip velocity. The results show the special structure of spiral oil wedge and the increase of eccentricity ratio make slip more difficult to occur. With the decrease of initial limiting shear stress, pressure, carrying capacity and friction drag decrease. Wall slip has an effect on the oil film rupture position, positive pressure area, and pressure peak. Wall slip occurs first in the large shear stress, the small clearance, and the envelop zone. The slip position and area influence each other in the sleeve and axial surface.