Inertia Effects in Rheodynamic Lubrication of an Externally Pressurized Converging Thrust Bearing using Herschel-Bulkley Fluids

Abstract

Extreme industrial conditions require a bearing which can withstand high-speed operations, heavy load, high stiffness and so on. Therefore in this study, the combined effects of fluid inertia forces and non-Newtonian characteristic with Herschel-Bulkley fluid as lubricant in an externally pressurized converging thrust bearing have been contemplated. Avoiding complex calculation, the term inertia in the momentum equation is estimated by the mean value average method across the film thickness. A mathematical model for converged thrust bearing has been introduced. Using appropriate boundary conditions, thickness of the core, velocity profile, film pressure and the load carrying capacity of the bearing for various values of Herschel-Bulkley number (N), Reynolds number (Re), Power-law index (n) and angle of convergence (φ) have been numerically computed. Having worked with an externally pressurized flow through a narrow clearance between two convergent disks symmetrical with respect to r and z axis, it is found that the converged bearing performance such as pressure distribution and load carrying capacity increases notably. The results obtained in this study is found to be in agreement with the results of Jayakaran et al. (2012), for a particular case.

Keywords

• rheodynamic lubrication; externally pressurized thrust bearing; herschel-bulkley lubricants
• angle of convergence; inertia effects.