Journal Bearing Design Tool : Time-dependent Analysis of Bearing Film Thickness, Power Loss and Load Response

Journal bearings are widely used in rotating machinery, e.g. turbines and internal combustion engines. With the ability to analyse bearing behaviour early in the product development process (PDP), problems can be avoided and a shorter time-to-market can be achieved. A simulation tool for journal bearings has been developed in the commercial software Comsol Multiphysics, which utilises the finite element method (FEM) as numerical technique. The simulation tool enables analysis of different bearing dimensions with variations in the geometry, such as grooves. The geometry is either imported from computer aided design (CAD) software or generated from input data within Comsol.Different predefined modules within Comsol have been utilised to increase the ease of use of the tool, e.g. thin film flow and structural mechanics theory. This also allows for coupling between physics to be made in a straightforward manner.Cavitation has been taken into consideration by using a cavitation model that is based on scaling the density and viscosity of the lubricant, depending on pressure. This cavitation model is mass conserving and fulfils the Jakobsson-Floberg-Olsson (JFO) rupture and reformation boundary conditions. Other phenomena like power losses, deformation and stress have also been included.Different parameters have been investigated in both static- and dynamic analyses, where various cases have been compared to data from previous studies in the field, in order to validate the simulation tool. The load response for bearings has been investigated and e.g. an increased stability for higher loads in the case of unbalance in the journal has been observed.Validerat; 20160608 (global_studentproject_submitter