The effects of angle of convergence on the shape and thickness of the core are analyzed theoretically by considering variable film thickness in an externally pressurized circular thrust bearing. Using the assumptions of the lubrication theory, modified Reynold’s equation and the governing equations are obtained. Using the boundary conditions of the problem in the constitutive equations we get the velocity of the core region as well as flow region. By considering the equilibrium of an element in the yield surface, an algebraic equation to determine the thickness of the yield surface is derived. Numerical solutions are obtained for the thickness of yield surface and velocities for various values of Bingham Numbers and the angle of convergence.

Thrust bearing are innately developed to withstand axial load. When the bearing is subjected to high speed operations, heavy load, high stiffness etc., suggesting a change in the design of the bearing plays a vital role in its performance. Friction is developed between the circular plates while the bearing operates. To reduce this friction, the bearing is lubricated with lubricants such as mineral oil, greases etc., Generally, lubricants are classified into two types that is Newtonian and non-Newtonian. However, non-Newtonian fluids characterized by an yield value such as Bingham, Casson and Herschel Bulkley, are attracting the tribologists, at present. And also, the study of fluid inertia on thrust bearing is required to optimize the performance of the bearings. In this investigation, we have ventured to analyze the performance of the bearing by considering the combined effects of fluid inertia forces and non-Newtonian characteristic with Bingham fluid as lubricant in an externally pressurized converging circular thrust bearing. Such studies will be useful in the design of the bearing for the optimum performance using the appropriate lubricant in various machineries operating in an extreme condition in the industries. Averaging the inertia terms over film thickness and defining a modified pressure gradient, the rheodynamic lubrication equation containing inertia terms has been analyzed. Using the appropriate boundary conditions and considering externally pressurized flow in narrow clearance between two converging discs is symmetric w.r.t r and z axis, the velocity distributions, the modified pressure gradient and thereby the film pressure and the load capacity of the bearing have been obtained numerically for different values of Bingham number, Reynolds number and angle of convergence. In addition to that, the effects of the inertia forces, non-Newtonian characteristics and angle of convergence on the bearing performances have been discussed.

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In this research paper we have theoretically analyzed the effects of the angle of convergence and the non-Newtonian characteristics on the performance of an externally pressurized converging circular thrust bearing using Bingham fluid as the lubricant. Since Bingham lubricants are known to have a characterized yield value, there will be a formation of unyielding core in the region between the plates of the bearing. The solutions are obtained for the pressure and load carrying capacity of the bearing for various values of Bingham number and the angle of convergence. The effects of the Non-Newtonian characteristics of the lubricant and the angle of convergence on the performance of the bearing are discussed.

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