Mathematical model of a journal bearing with low-melting and porous coating in its structure on different contacting surfaces with incomplete filling of operating clearance

Abstract

The authors consider the development of a mathematical design model of an infinite journal bearing lubricated with a lubricant with Newtonian rheological properties and a melt of a low-melting metal alloy covering the surface of the bearing bush, as well as a porous coating on the surface of the shaft, taking into consideration the dependence of the viscosity characteristics of the lubricant, the melt and the permeability of the porous coatings on the pressure with incomplete filling of the operating clearance. The authors found asymptotic solution of the system of differential equations with respect to the parameter K due to the melt and the rate of dissipation of mechanical energy and the exact self-similar solution for the zero approximation without regard for the melt and the first approximation taking into consideration the melt. This solution was found according to the equation of motion of a viscous incompressible fluid for a thin layer, the equations of continuity, Darcy equation and the equation determining, taking into account the expression for the rate of dissipation of mechanical energy, the profile of the molten contour of the bearing bush with regard to the dependence of the permeability of the porous coating, the viscosity of the lubricant depending on pressure. As a result, the fields of velocities and pressures in the lubricating and porous layers were determined taking into consideration the dependence of the lubricant viscosity and the permeability of the porous coating on pressure, as well as the function Φ1(θ), reasoned by the melt of the bearing bush surface. In addition, the main performance characteristics were determined: load-bearing capacity and friction force.