Enhancement of steady state performance of hydrodynamic journal bearing using chevron-shaped surface texture

Abstract

In the present study, the optimum design parameters of chevron-shaped surface texture have been determined for the steady state performance enhancement of a hydrodynamic journal bearing. The fluid flow governing Reynolds equation has been solved using the finite element method, assuming iso-viscous and Newtonian fluid to obtain the static performance characteristics of textured hydrodynamic journal bearing. Different texture depths, areas and distributions have been numerically simulated and a set of optimum texture parameters has been determined based on the maximum performance enhancement ratio. The numerically obtained results indicate that surface texturing can improve bearing performance if the textured region is placed in the pressure build-up region. Moreover, surface texturing is the most effective at bearing performance enhancement when the bearing operates at lower eccentricity ratios. The performance enhancement ratio, which is the ratio of load-carrying capacity to coefficient of friction is found to be maximum at texture depth of 0.4, k = 0.3, textured zone located in the increasing pressure region and eccentricity ratio of 0.2.

Dynamic and stability performance improvement of the hydrodynamic bearing by using triangular-shaped textures

“…The nondimensional governing Reynold's equation having laminar flow and iso-viscous Newtonian lubricant for a hydrodynamic bearing is given by Sharma et al. 17 as where F¯0, F¯1, and F¯2 are viscosity functions and are given by the following expressions F¯0=∫0 11μ¯dz¯, F¯1=∫0 1z¯μ¯dz¯ and F¯2=∫0 1z¯μ¯(z¯-F¯…”

“…The minimum fluid film thickness for triangular-shaped textured hydrodynamic bearing is given by Sharma et al. 17 where XJ and ZJ = journal center coordinates at equilibrium position and Δh¯ = variation in fluid film thickness due to triangular-shaped textures on the bearing surface and its value is given by following equation given by Qiu et al. 18 where x l = local coordinates inside unit cell in circumferential direction and y l = local coordinates inside unit cell in axial direction.…”

“…After districitization of lubricant flow domain with four-noded quadrilateral isoparametric elements and by using Galerkin's orthogonality criterion, the global system equation is obtained as Sharma et al. 17 …”

“…The boundary conditions for lubricant flow domain are Sharma et al. 17 Nodes on the boundary of lubricant flow domain are given as zero pressure Reynold's boundary condition is adopted to take cavitation into consideration. Therefore, pressure is taken as zero (where splitting up/cavitation occurs) …”

Finite element analysis of multirecess hybrid spherical journal bearing system

“…Performance enhancement ratio (PER) has been defined based on the load carrying capacity and friction coefficient criterions. 26,27 The following mathematical relation expresses the PER …”