Numerical Solution Of Hydrodynamic Journal Bearing

With the development of modern industry, rotating machinery tends to be more high-speed and high-power and all bearing performance is required to better. As a result of hydrodynamic lubrication bearings (referred to as journal bearing) for high-speed, heavy-duty, high accuracy, corrosion medium, small radial structure and so on, journal bearing are widely used. It is therefore necessary to in-depth study journal bearing because it has a strong practical significance. When the journal bearing working, lubricant friction produce heat and part of it is taken away by the flow oil and others will lead to increased bearing temperature. As bearing temperature rise lead to thermal stress generated, solving the temperature field is a prerequisite for calculating thermal stress. Analysis of temperature distribution may limit the emergence of high temperature phenomenon so as not to block the material to soften and film damage and reduce the carrying capacity of bearing.In this paper journal bearing will be analyzed and film temperature field and pressure field and bearing stress field are calculated. Traditional way to calculate the journal bearing lubricant is solving the Reynolds equation and Summerfield and Reynolds boundary conditions are used to determine the lubricant boundary. Solving journal bearing by this approach has not considered the case of lubricant cavitations and the result has no sub-atmospheric pressure. This article will calculate lubricant pressure in these boundary conditions and then calculate more accurate lubricant pressure with the phenomenon of cavitations. Obtain the lubricant temperature field when the viscosity change with temperature and analyze the distribution of lubricant temperature. Compare it with the temperature when the viscosity is constant and discuss the influence of lubricant viscosity on the temperature. And then apply the finite element method and calculate maximum stress value and distribution under lubricant pressure load and temperature load separately and calculate the strain and radial deformation. This provides the basis for the bearing design and failure analysis.Through the calculation of this article the bearing characteristic curve when viscosity changes with temperature can be obtained, including Sommerfeld number, normalized friction coefficient, lubricant flow rate and side leakage over lubricant flow rate. It provides a more accurate data for bearing research and has a strong practical value.