Oil flow in plain steadily loaded journal bearings: Realistic predictions using rapid techniques

Abstract

The aim of the paper is to produce a rapid calculation method for predicting lubricant flow in plain cylindrical journal bearings. Lubricant flow data, already available from rigorous solutions considering the effect of film reformation, are used together with experimental evidence to develop unique graphical aids and flow prediction equations. These equations, although developed from specific flow data, are of a general form and therefore will be applicable to a wide range of different bearing operating conditions. Graphical aids, from which the flow equations are derived, give normalized actual flow as a function of normalized hydrodynamic flow for different groove geometries. The main input parameters, namely a hydrodynamic flow term Qh and a feed pressure flow term Qp, are easy to derive and have been in common use in bearing design techniques over many decades. The new design aids, in chart and equation form, give realistic flow predictions for bearings with an oil hole, a groove opposite the load line, an axial groove at the maximum film thickness position and the commonly used case of a bearing with two axial grooves. The flow prediction equations are supported by experimental data.