Application of Regularised Cavitation Algorithm for Transient Analysis of Rotors Supported in Floating Ring Bearings

In order to analyse the dynamical behaviour of fast-rotating, lightly loaded rotors with floating ring bearings, which mainly occur in turbochargers, a suitable simulation method is required. For that purpose, an online solution of the Reynolds differential equation within a transient rotor dynamic simulation is applied. In addition to the hydraulic coupling of inner and outer lubrication film in the floating ring bearing, a mass-preserving cavitation model is introduced. Therefore, the algorithm of Elrod is adopted by use of a regularisation scheme in the differential equation in order to eliminate the originally occurring numerical problems under transient loads. The developed program is validated based on data available in the literature, as well as on the basis of test rig measurements for a passenger car turbocharger. Finally, the achievable result quality is examined in relation to the computational cost under successive reduction of the hydrodynamic modeling depth.