Effects of new micro-pocketed bore surface topographies on the performance behaviours of aerodynamic journal bearing

Abstract

This paper presents the exploration for improving the static and dynamic performance behaviours of a self-acting rigid gas journal bearing employing some new conceived micro-depth pocketed surface topographies at the bore. The conceived micro-pockets comprise of relatively large size rectangular pocket having micro-depth at bearing bore in the converging zone followed by placing of different designs of sub-pockets at the trailing edge of the previous one in the direction of journal rotation. The form of equation achieved from Patir and Cheng’s model for the case of hydrodynamic lubrication regime and the related dynamic pressure equations have been solved using the finite volume method discretisation scheme followed by the solution of the algebraic equations using the Gauss-Seidel iterative method. The minimum film thickness, frictional force, side leakage, bearing dynamic coefficients, effective stiffness, effective damping, and critical mass parameters have been investigated with each new bore surface topography and compared with the performances of conventional aerodynamic journal bearing. Substantial improvements in both static and dynamic performances have been found with the new micro-pocketed bore surface topographies as compared to conventional one. Moreover, the established best bore design has produced significant increase (21%) in minimum film thickness, substantial reduction (12%) in coefficient of friction, and excellent improvement (170%) in the stability parameter (critical mass) as compared to the conventional case.

Performance improvement of a radial ball bearing using a micro-groove on stationary outer race

“…23 Moreover, highly hydrogenated DLC coatings has been used to achieve lower frictional torque on angular contact bearings in space application. 24 In recent years, surface textures with nano/micro geometries comprising of spherical/ellipsoidal, [4][5][6][23][24][25][26][27][28][29][30][31][32][33] triangular dimples, 34 micro-grooves/pockets, 8,12,15,32,[35][36][37][38] and bionic shapes 7,38 have been employed in thrust ball bearings, 4,5,8,12 radial ball bearing, 6,7,13,14 journal bearings, 32,37,38 and gears 33,39 to improve the tribological parameters. The tribodynamic performances such as vibration, [4][5][6][7][8]25,33,[39]…”

“…In recent years, surface textures with nano/micro geometries comprising of spherical/ellipsoidal, 4–6,23–33 triangular dimples, 34 micro- grooves/pockets, 8,12,15,32,35–38 and bionic shapes 7,38 have been employed in thrust ball bearings, 4,5,8,12 radial ball bearing, 6,7,13,14 journal bearings, 32,37,38 and gears 33,39 to improve the tribological parameters. The tribodynamic performances such as vibration, 4–8,25,33,39–42 film thickness 32,37,39,43 and friction coefficient/frictional torque 4–8,12,25…”

Effects of Snake-Bioinspired Surface Texture on the Finger-Sealing Performance under Varied Working Conditions

“…In addition, changing the contact stress distribution and reducing the direct contact between the interface to reduce friction and wear [19]. (2) Under boundary to mixed lubrication, acting as microreservoirs and generating a large number of micro-fluidic film bearings to enhance the lubrication of the frictional substrate [20]. (3) Under hydrodynamic lubrication, generating hydrodynamic pressure to improve the load-carrying capacity [21].…”

Two-way Fluid Structure Interaction Analysis of Single Pad Externally Adjustable Fluid Film Bearing

“…It is impossible to get analytical solutions for complicated flows and geometry. Various researchers have used analytical and numerical methods such as the finite element method (FEM), [25][26][27] finite difference method (FDM), [28][29][30] , and finite volume method (FVM) [31][32][33] to capture the flow characteristics in a journal bearing. The computational domain is discretized in these numerical methods into small segments, so-called control volumes.…”