Method of investigating the elastohydrodynamic contact in slide bearings with compressible and incompressible lubrication

Abstract

An algorithm of solving the problem of elastohydrodynamic contact is presented in the paper. It is used to calculate characteristics of journal and thrust bearings with oil or gas lubrication. The algorithm is based on simultaneous solution of the problem of lubrication flow in the gap created by the bearing sliding surfaces and the problem of specifying the change in the gap shape due to the shift of position and deformations of sliding surfaces caused by lubrication pressure in the gap. Modifications of Reynolds equation describing incompressible (oil) and compressible (gas) lubrication flow in journal and thrust bearing are used for the calculation of bearing characteristics. The finite-element method is used to solve the Reynolds equation. Lagrange multipliers are used to ensure closedness of the rectangular region for a journal bearing.  A step-by-step process with error self-correction at each step is applied for solving the nonlinear Reynolds equation for compressible lubrication. The shape of the gap in bearings with incompressible lubrication is defined by calculating the equilibrium pad position in a bearing taking into account the deformations of siding surfaces and bearing parts under the action of lubrication pressure. The shape of the gap in gas bearings is defined by the deformations of elastic foils. These deformations are calculated when solving the problem of deformation and contact interaction of the foils with each other and with the bearing housing under the action of lubrication pressure. The presented method of calculation of elastohydrodynamic contact in slide bearings allows taking into account the design features of physical products for the analysis of rotor supports characteristics.